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Microsoft Corp. today released software updates to quash 130 security bugs in its Windows operating systems and related software, including at least five flaws that are already seeing active exploitation. Meanwhile, Apple customers have their own zero-day woes again this month: On Monday, Apple issued (and then quickly pulled) an emergency update to fix a zero-day vulnerability that is being exploited on MacOS and iOS devices.
On July 10, Apple pushed a “Rapid Security Response” update to fix a code execution flaw in the Webkit browser component built into iOS, iPadOS, and macOS Ventura. Almost as soon as the patch went out, Apple pulled the software because it was reportedly causing problems loading certain websites. MacRumors says Apple will likely re-release the patches when the glitches have been addressed.
Launched in May, Apple’s Rapid Security Response updates are designed to address time-sensitive vulnerabilities, and this is the second month Apple has used it. July marks the sixth month this year that Apple has released updates for zero-day vulnerabilities — those that get exploited by malware or malcontents before there is an official patch available.
If you rely on Apple devices and don’t have automatic updates enabled, please take a moment to check the patch status of your various iDevices. The latest security update that includes the fix for the zero-day bug should be available in iOS/iPadOS 16.5.1, macOS 13.4.1, and Safari 16.5.2.
On the Windows side, there are at least four vulnerabilities patched this month that earned high CVSS (badness) scores and that are already being exploited in active attacks, according to Microsoft. They include CVE-2023-32049, which is a hole in Windows SmartScreen that lets malware bypass security warning prompts; and CVE-2023-35311 allows attackers to bypass security features in Microsoft Outlook.
The two other zero-day threats this month for Windows are both privilege escalation flaws. CVE-2023-32046 affects a core Windows component called MSHTML, which is used by Windows and other applications, like Office, Outlook and Skype. CVE-2023-36874 is an elevation of privilege bug in the Windows Error Reporting Service.
Many security experts expected Microsoft to address a fifth zero-day flaw — CVE-2023-36884 — a remote code execution weakness in Office and Windows.
“Surprisingly, there is no patch yet for one of the five zero-day vulnerabilities,” said Adam Barnett, lead software engineer at Rapid7. “Microsoft is actively investigating publicly disclosed vulnerability, and promises to update the advisory as soon as further guidance is available.”
Barnett notes that Microsoft links exploitation of this vulnerability with Storm-0978, the software giant’s name for a cybercriminal group based out of Russia that is identified by the broader security community as RomCom.
“Exploitation of CVE-2023-36884 may lead to installation of the eponymous RomCom trojan or other malware,” Barnett said. “[Microsoft] suggests that RomCom / Storm-0978 is operating in support of Russian intelligence operations. The same threat actor has also been associated with ransomware attacks targeting a wide array of victims.”
Microsoft’s advisory on CVE-2023-36884 is pretty sparse, but it does include a Windows registry hack that should help mitigate attacks on this vulnerability. Microsoft has also published a blog post about phishing campaigns tied to Storm-0978 and to the exploitation of this flaw.
Barnett said it’s while it’s possible that a patch will be issued as part of next month’s Patch Tuesday, Microsoft Office is deployed just about everywhere, and this threat actor is making waves.
“Admins should be ready for an out-of-cycle security update for CVE-2023-36884,” he said.
Microsoft also today released new details about how it plans to address the existential threat of malware that is cryptographically signed by…wait for it….Microsoft.
In late 2022, security experts at Sophos, Trend Micro and Cisco warned that ransomware criminals were using signed, malicious drivers in an attempt to evade antivirus and endpoint detection and response (EDR) tools.
In a blog post today, Sophos’s Andrew Brandt wrote that Sophos identified 133 malicious Windows driver files that were digitally signed since April 2021, and found 100 of those were actually signed by Microsoft. Microsoft said today it is taking steps to ensure those malicious driver files can no longer run on Windows computers.
As KrebsOnSecurity noted in last month’s story on malware signing-as-a-service, code-signing certificates are supposed to help authenticate the identity of software publishers, and provide cryptographic assurance that a signed piece of software has not been altered or tampered with. Both of these qualities make stolen or ill-gotten code-signing certificates attractive to cybercriminal groups, who prize their ability to add stealth and longevity to malicious software.
Dan Goodin at Ars Technica contends that whatever Microsoft may be doing to keep maliciously signed drivers from running on Windows is being bypassed by hackers using open source software that is popular with video game cheaters.
“The software comes in the form of two software tools that are available on GitHub,” Goodin explained. “Cheaters use them to digitally sign malicious system drivers so they can modify video games in ways that give the player an unfair advantage. The drivers clear the considerable hurdle required for the cheat code to run inside the Windows kernel, the fortified layer of the operating system reserved for the most critical and sensitive functions.”
Meanwhile, researchers at Cisco’s Talos security team found multiple Chinese-speaking threat groups have repurposed the tools—one apparently called “HookSignTool” and the other “FuckCertVerifyTimeValidity.”
“Instead of using the kernel access for cheating, the threat actors use it to give their malware capabilities it wouldn’t otherwise have,” Goodin said.
For a closer look at the patches released by Microsoft today, check out the always-thorough Patch Tuesday roundup from the SANS Internet Storm Center. And it’s not a bad idea to hold off updating for a few days until Microsoft works out any kinks in the updates: AskWoody.com usually has the lowdown on any patches that may be causing problems for Windows users.
And as ever, please consider backing up your system or at least your important documents and data before applying system updates. If you encounter any problems with these updates, please drop a note about it here in the comments.
We learned some remarkable new details this week about the recent supply-chain attack on VoIP software provider 3CX. The lengthy, complex intrusion has all the makings of a cyberpunk spy novel: North Korean hackers using legions of fake executive accounts on LinkedIn to lure people into opening malware disguised as a job offer; malware targeting Mac and Linux users working at defense and cryptocurrency firms; and software supply-chain attacks nested within earlier supply chain attacks.
Researchers at ESET say this job offer from a phony HSBC recruiter on LinkedIn was North Korean malware masquerading as a PDF file.
In late March 2023, 3CX disclosed that its desktop applications for both Windows and macOS were compromised with malicious code that gave attackers the ability to download and run code on all machines where the app was installed. 3CX says it has more than 600,000 customers and 12 million users in a broad range of industries, including aerospace, healthcare and hospitality.
3CX hired incident response firm Mandiant, which released a report on Wednesday that said the compromise began in 2022 when a 3CX employee installed a malware-laced software package distributed via an earlier software supply chain compromise that began with a tampered installer for X_TRADER, a software package provided by Trading Technologies.
“This is the first time Mandiant has seen a software supply chain attack lead to another software supply chain attack,” reads the April 20 Mandiant report.
Mandiant found the earliest evidence of compromise uncovered within 3CX’s network was through the VPN using the employee’s corporate credentials, two days after the employee’s personal computer was compromised.
“Eventually, the threat actor was able to compromise both the Windows and macOS build environments,” 3CX said in an April 20 update on their blog.
Mandiant concluded that the 3CX attack was orchestrated by the North Korean state-sponsored hacking group known as Lazarus, a determination that was independently reached earlier by researchers at Kaspersky Lab and Elastic Security.
Mandiant found the compromised 3CX software would download malware that sought out new instructions by consulting encrypted icon files hosted on GitHub. The decrypted icon files revealed the location of the malware’s control server, which was then queried for a third stage of the malware compromise — a password stealing program dubbed ICONICSTEALER.
The double supply chain compromise that led to malware being pushed out to some 3CX customers. Image: Mandiant.
Meanwhile, the security firm ESET today published research showing remarkable similarities between the malware used in the 3CX supply chain attack and Linux-based malware that was recently deployed via fake job offers from phony executive profiles on LinkedIn. The researchers said this was the first time Lazarus had been spotted deploying malware aimed at Linux users.
As reported in a series last summer here, LinkedIn has been inundated this past year by fake executive profiles for people supposedly employed at a range of technology, defense, energy and financial companies. In many cases, the phony profiles spoofed chief information security officers at major corporations, and some attracted quite a few connections before their accounts were terminated.
Mandiant, Proofpoint and other experts say Lazarus has long used these bogus LinkedIn profiles to lure targets into opening a malware-laced document that is often disguised as a job offer. This ongoing North Korean espionage campaign using LinkedIn was first documented in August 2020 by ClearSky Security, which said the Lazarus group operates dozens of researchers and intelligence personnel to maintain the campaign globally.
Microsoft Corp., which owns LinkedIn, said in September 2022 that it had detected a wide range of social engineering campaigns using a proliferation of phony LinkedIn accounts. Microsoft said the accounts were used to impersonate recruiters at technology, defense and media companies, and to entice people into opening a malicious file. Microsoft found the attackers often disguised their malware as legitimate open-source software like Sumatra PDF and the SSH client Putty.
Microsoft attributed those attacks to North Korea’s Lazarus hacking group, although they’ve traditionally referred to this group as “ZINC“. That is, until earlier this month, when Redmond completely revamped the way it names threat groups; Microsoft now references ZINC as “Diamond Sleet.”
The ESET researchers said they found a new fake job lure tied to an ongoing Lazarus campaign on LinkedIn designed to compromise Linux operating systems. The malware was found inside of a document that offered an employment contract at the multinational bank HSBC.
“A few weeks ago, a native Linux payload was found on VirusTotal with an HSBC-themed PDF lure,” wrote ESET researchers Peter Kalnai and Marc-Etienne M.Leveille. “This completes Lazarus’s ability to target all major desktop operating systems. In this case, we were able to reconstruct the full chain, from the ZIP file that delivers a fake HSBC job offer as a decoy, up until the final payload.”
ESET said the malicious PDF file used in the scheme appeared to have a file extension of “.pdf,” but that this was a ruse. ESET discovered that the dot in the filename wasn’t a normal period but instead a Unicode character (U+2024) representing a “leader dot,” which is often used in tables of contents to connect section headings with the page numbers on which those sections begin.
“The use of the leader dot in the filename was probably an attempt to trick the file manager into treating the file as an executable instead of a PDF,” the researchers continued. “This could cause the file to run when double-clicked instead of opening it with a PDF viewer.”
ESET said anyone who opened the file would see a decoy PDF with a job offer from HSBC, but in the background the executable file would download additional malware payloads. The ESET team also found the malware was able to manipulate the program icon displayed by the malicious PDF, possibly because fiddling with the file extension could cause the user’s system to display a blank icon for the malware lure.
Kim Zetter, a veteran Wired.com reporter and now independent security journalist, interviewed Mandiant researchers who said they expect “many more victims” will be discovered among the customers of Trading Technologies and 3CX now that news of the compromised software programs is public.
“Mandiant informed Trading Technologies on April 11 that its X_Trader software had been compromised, but the software maker says it has not had time to investigate and verify Mandiant’s assertions,” Zetter wrote in her Zero Day newsletter on Substack. For now, it remains unclear whether the compromised X_Trader software was downloaded by people at other software firms.
If there’s a silver lining here, the X_Trader software had been decommissioned in April 2020 — two years before the hackers allegedly embedded malware in it.
“The company hadn’t released new versions of the software since that time and had stopped providing support for the product, making it a less-than-ideal vector for the North Korean hackers to infect customers,” Zetter wrote.
Microsoft today released software updates to plug 100 security holes in its Windows operating systems and other software, including a zero-day vulnerability that is already being used in active attacks. Not to be outdone, Apple has released a set of important updates addressing two zero-day vulnerabilities that are being used to attack iPhones, iPads and Macs.
On April 7, Apple issued emergency security updates to fix two weaknesses that are being actively exploited, including CVE-2023-28206, which can be exploited by apps to seize control over a device. CVE-2023-28205 can be used by a malicious or hacked website to install code.
Both vulnerabilities are addressed in iOS/iPadOS 16.4.1, iOS 15.7.5, and macOS 12.6.5 and 11.7.6. If you use Apple devices and you don’t have automatic updates enabled (they are on by default), you should probably take care of that soon as detailed instructions on how to attack CVE-2023-28206 are now public.
Microsoft’s bevy of 100 security updates released today include CVE-2023-28252, which is a weakness in Windows that Redmond says is under active attack. The vulnerability is in the Windows Common Log System File System (CLFS) driver, a core Windows component that was the source of attacks targeting a different zero-day vulnerability in February 2023.
“If it seems familiar, that’s because there was a similar 0-day patched in the same component just two months ago,” said Dustin Childs at the Trend Micro Zero Day Initiative. “To me, that implies the original fix was insufficient and attackers have found a method to bypass that fix. As in February, there is no information about how widespread these attacks may be. This type of exploit is typically paired with a code execution bug to spread malware or ransomware.”
According to the security firm Qualys, this vulnerability has been leveraged by cyber criminals to deploy Nokoyawa ransomware.
“This is a relatively new strain for which there is some open source intel to suggest that it is possibly related to Hive ransomware – one of the most notable ransomware families of 2021 and linked to breaches of over 300+ organizations in a matter of just a few months,” said Bharat Jogi, director of vulnerability and threat research at Qualys.
Jogi said while it is still unclear which exact threat actor is targeting CVE-2023-28252, targets have been observed in South and North America, regions across Asia and at organizations in the Middle East.
Satnam Narang at Tenable notes that CVE-2023-28252 is also the second CLFS zero-day disclosed to Microsoft by researchers from Mandiant and DBAPPSecurity (CVE-2022-37969), though it is unclear if both of these discoveries are related to the same attacker.
Seven of the 100 vulnerabilities Microsoft fixed today are rated “Critical,” meaning they can be used to install malicious code with no help from the user. Ninety of the flaws earned Redmond’s slightly less-dire “Important” label, which refers to weaknesses that can be used to undermine the security of the system but which may require some amount of user interaction.
Narang said Microsoft has rated nearly 90% of this month’s vulnerabilities as “Exploitation Less Likely,” while just 9.3% of flaws were rated as “Exploitation More Likely.” Kevin Breen at Immersive Labs zeroed in on several notable flaws in that 9.3%, including CVE-2023-28231, a remote code execution vulnerability in a core Windows network process (DHCP) with a CVSS score of 8.8.
“‘Exploitation more likely’ means it’s not being actively exploited but adversaries may look to try and weaponize this one,” Breen said. “Micorosft does note that successful exploitation requires an attacker to have already gained initial access to the network. This could be via social engineering, spear phishing attacks, or exploitation of other services.”
Breen also called attention to CVE-2023-28220 and CVE-2023-28219 — a pair of remote code execution vulnerabilities affecting Windows Remote Access Servers (RAS) that also earned Microsoft’s “exploitation more likely” label.
“An attacker can exploit this vulnerability by sending a specially crafted connection request to a RAS server, which could lead to remote code execution,” Breen said. While not standard in all organizations, RAS servers typically have direct access from the Internet where most users and services are connected. This makes it extremely enticing for attackers as they don’t need to socially engineer their way into an organization. They can simply scan the internet for RAS servers and automate the exploitation of vulnerable devices.”
For more details on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
Google says it has suspended the app for the Chinese e-commerce giant Pinduoduo after malware was found in versions of the software. The move comes just weeks after Chinese security researchers published an analysis suggesting the popular e-commerce app sought to seize total control over affected devices by exploiting multiple security vulnerabilities in a variety of Android-based smartphones.
In November 2022, researchers at Google’s Project Zero warned about active attacks on Samsung mobile phones which chained together three security vulnerabilities that Samsung patched in March 2021, and which would have allowed an app to add or read any files on the device.
Google said it believes the exploit chain for Samsung devices belonged to a “commercial surveillance vendor,” without elaborating further. The highly technical writeup also did not name the malicious app in question.
On Feb. 28, 2023, researchers at the Chinese security firm DarkNavy published a blog post purporting to show evidence that a major Chinese ecommerce company’s app was using this same three-exploit chain to read user data stored by other apps on the affected device, and to make its app nearly impossible to remove.
DarkNavy likewise did not name the app they said was responsible for the attacks. In fact, the researchers took care to redact the name of the app from multiple code screenshots published in their writeup. DarkNavy did not respond to requests for clarification.
“At present, a large number of end users have complained on multiple social platforms,” reads a translated version of the DarkNavy blog post. “The app has problems such as inexplicable installation, privacy leakage, and inability to uninstall.”
Update, March 27, 1:24 p.m. ET: Dan Goodin over at Ars Technica has an important update on this story that indicates the Pinduoduo code was exploiting a zero-day vulnerability in Android — not Samsung. From that piece:
“A preliminary analysis by Lookout found that at least two off-Play versions of Pinduoduo for Android exploited CVE-2023-20963, the tracking number for an Android vulnerability Google patched in updates that became available to end users two weeks ago. This privilege-escalation flaw, which was exploited prior to Google’s disclosure, allowed the app to perform operations with elevated privileges. The app used these privileges to download code from a developer-designated site and run it within a privileged environment.
“The malicious apps represent “a very sophisticated attack for an app-based malware,” Christoph Hebeisen, one of three Lookout researchers who analyzed the file, wrote in an email. “In recent years, exploits have not usually been seen in the context of mass-distributed apps. Given the extremely intrusive nature of such sophisticated app-based malware, this is an important threat mobile users need to protect against.”
On March 3, 2023, a denizen of the now-defunct cybercrime community BreachForums posted a thread which noted that a unique component of the malicious app code highlighted by DarkNavy also was found in the ecommerce application whose name was apparently redacted from the DarkNavy analysis: Pinduoduo.
A Mar. 3, 2023 post on BreachForums, comparing the redacted code from the DarkNavy analysis with the same function in the Pinduoduo app available for download at the time.
On March 4, 2023, e-commerce expert Liu Huafang posted on the Chinese social media network Weibo that Pinduoduo’s app was using security vulnerabilities to gain market share by stealing user data from its competitors. That Weibo post has since been deleted.
On March 7, the newly created Github account Davinci1010 published a technical analysis claiming that until recently Pinduoduo’s source code included a “backdoor,” a hacking term used to describe code that allows an adversary to remotely and secretly connect to a compromised system at will.
That analysis includes links to archived versions of Pinduoduo’s app released before March 5 (version 6.50 and lower), which is when Davinci1010 says a new version of the app removed the malicious code.
Pinduoduo has not yet responded to requests for comment. Pinduoduo parent company PDD Holdings told Reuters Google has not shared details about why it suspended the app.
The company told CNN that it strongly rejects “the speculation and accusation that Pinduoduo app is malicious just from a generic and non-conclusive response from Google,” and said there were “several apps that have been suspended from Google Play at the same time.”
Pinduoduo is among China’s most popular e-commerce platforms, boasting approximately 900 million monthly active users.
Most of the news coverage of Google’s move against Pinduoduo emphasizes that the malware was found in versions of the Pinduoduo app available outside of Google’s app store — Google Play.
“Off-Play versions of this app that have been found to contain malware have been enforced on via Google Play Protect,” a Google spokesperson said in a statement to Reuters, adding that the Play version of the app has been suspended for security concerns.
However, Google Play is not available to consumers in China. As a result, the app will still be available via other mobile app stores catering to the Chinese market — including those operated by Huawei, Oppo, Tencent and VIVO.
Google said its ban did not affect the PDD Holdings app Temu, which is an online shopping platform in the United States. According to The Washington Post, four of the Apple App Store’s 10 most-downloaded free apps are owned by Chinese companies, including Temu and the social media network TikTok.
The Pinduoduo suspension comes as lawmakers in Congress this week are gearing up to grill the CEO of TikTok over national security concerns. TikTok, which is owned by Beijing-based ByteDance, said last month that it now has roughly 150 million monthly active users in the United States.
A new cybersecurity strategy released earlier this month by the Biden administration singled out China as the greatest cyber threat to the U.S. and Western interests. The strategy says China now presents the “broadest, most active, and most persistent threat to both government and private sector networks,” and says China is “the only country with both the intent to reshape the international order and, increasingly, the economic, diplomatic, military, and technological power to do so.”
Microsoft on Tuesday released updates to quash at least 74 security bugs in its Windows operating systems and software. Two of those flaws are already being actively attacked, including an especially severe weakness in Microsoft Outlook that can be exploited without any user interaction.
The Outlook vulnerability (CVE-2023-23397) affects all versions of Microsoft Outlook from 2013 to the newest. Microsoft said it has seen evidence that attackers are exploiting this flaw, which can be done without any user interaction by sending a booby-trapped email that triggers automatically when retrieved by the email server — before the email is even viewed in the Preview Pane.
While CVE-2023-23397 is labeled as an “Elevation of Privilege” vulnerability, that label doesn’t accurately reflect its severity, said Kevin Breen, director of cyber threat research at Immersive Labs.
Known as an NTLM relay attack, it allows an attacker to get someone’s NTLM hash [Windows account password] and use it in an attack commonly referred to as “Pass The Hash.”
“The vulnerability effectively lets the attacker authenticate as a trusted individual without having to know the person’s password,” Breen said. “This is on par with an attacker having a valid password with access to an organization’s systems.”
Security firm Rapid7 points out that this bug affects self-hosted versions of Outlook like Microsoft 365 Apps for Enterprise, but Microsoft-hosted online services like Microsoft 365 are not vulnerable.
The other zero-day flaw being actively exploited in the wild — CVE-2023-24880 — is a “Security Feature Bypass” in Windows SmartScreen, part of Microsoft’s slate of endpoint protection tools.
Patch management vendor Action1 notes that the exploit for this bug is low in complexity and requires no special privileges. But it does require some user interaction, and can’t be used to gain access to private information or privileges. However, the flaw can allow other malicious code to run without being detected by SmartScreen reputation checks.
Dustin Childs, head of threat awareness at Trend Micro’s Zero Day Initiative, said CVE-2023-24880 allows attackers to create files that would bypass Mark of the Web (MOTW) defenses.
“Protective measures like SmartScreen and Protected View in Microsoft Office rely on MOTW, so bypassing these makes it easier for threat actors to spread malware via crafted documents and other infected files that would otherwise be stopped by SmartScreen,” Childs said.
Seven other vulnerabilities Microsoft patched this week earned its most-dire “critical” severity label, meaning the updates address security holes that could be exploited to give the attacker full, remote control over a Windows host with little or no interaction from the user.
Also this week, Adobe released eight patches addressing a whopping 105 security holes across a variety of products, including Adobe Photoshop, Cold Fusion, Experience Manager, Dimension, Commerce, Magento, Substance 3D Stager, Cloud Desktop Application, and Illustrator.
For a more granular rundown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
Microsoft is sending the world a whole bunch of love today, in the form of patches to plug dozens of security holes in its Windows operating systems and other software. This year’s special Valentine’s Day Patch Tuesday includes fixes for a whopping three different “zero-day” vulnerabilities that are already being used in active attacks.
Microsoft’s security advisories are somewhat sparse with details about the zero-day bugs. Redmond flags CVE-2023-23376 as an “Important” elevation of privilege vulnerability in the Windows Common Log File System Driver, which is present in Windows 10 and 11 systems, as well as many server versions of Windows.
“Sadly, there’s just a little solid information about this privilege escalation,” said Dustin Childs, head of threat awareness at Trend Micro’s Zero Day Initiative. “Microsoft does note that the vulnerability would allow an attacker to exploit code as SYSTEM, which would allow them to completely take over a target. This is likely being chained with a remote code execution bug to spread malware or ransomware. Considering this was discovered by Microsoft’s Threat Intelligence Center, it could mean it was used by advanced threat actors. Either way, make sure you test and roll these fixes quickly.”
The zero-day CVE-2023-21715 is a weakness in Microsoft Office that Redmond describes as a “security feature bypass vulnerability.”
“Microsoft lists this as under active exploit, but they offer no info on how widespread these exploits may be,” Childs said. “Based on the write-up, it sounds more like a privilege escalation than a security feature bypass, but regardless, active attacks in a common enterprise application shouldn’t be ignored. It’s always alarming when a security feature is not just bypassed but exploited. Let’s hope the fix comprehensively addresses the problem.”
The third zero-day flaw already seeing exploitation is CVE-2023-21823, which is another elevation of privilege weakness — this one in the Microsoft Windows Graphic component. Researchers at cybersecurity forensics firm Mandiant were credited with reporting the bug.
Kevin Breen, director of cyber threat research at Immersive Labs, pointed out that the security bulletin for CVE-2023-21823 specifically calls out OneNote as being a vulnerable component for the vulnerability.
“In recent weeks, we have seen an increase in the use of OneNote files as part of targeted malware campaigns,” Breen said. “Patches for this are delivered via the app stores and not through the typical formats, so it’s important to double check your organization’s policies.”
Microsoft fixed another Office vulnerability in CVE-2023-21716, which is a Microsoft Word bug that can lead to remote code execution — even if a booby-trapped Word document is merely viewed in the preview pane of Microsoft Outlook. This security hole has a CVSS (severity) score of 9.8 out of a possible 10.
Microsoft also has more valentines for organizations that rely on Microsoft Exchange Server to handle email. Redmond patched three Exchange Server flaws (CVE-2023-21706, CVE-2023-21707, and CVE-2023-21529), all of which Microsoft says are remote code execution flaws that are likely to be exploited.
Microsoft said authentication is required to exploit these bugs, but then again threat groups that attack Exchange vulnerabilities also tend to phish targets for their Exchange credentials.
Microsoft isn’t alone in dropping fixes for scary, ill-described zero-day flaws. Apple on Feb. 13 released an update for iOS that resolves a zero-day vulnerability in Webkit, Apple’s open source browser engine. Johannes Ullrich at the SANS Internet Storm Center notes that in addition to the WebKit problem, Apple fixed a privilege escalation issue. Both flaws are fixed in iOS 16.3.1.
“This privilege escalation issue could be used to escape the browser sandbox and gain full system access after executing code via the WebKit vulnerability,” Ullrich warned.
On a lighter note (hopefully), Microsoft drove the final nail in the coffin for Internet Explorer 11 (IE11). According to Redmond, the out-of-support IE11 desktop application was permanently disabled on certain versions of Windows 10 on February 14, 2023 through a Microsoft Edge update.
“All remaining consumer and commercial devices that were not already redirected from IE11 to Microsoft Edge were redirected with the Microsoft Edge update. Users will be unable to reverse the change,” Microsoft explained. “Additionally, redirection from IE11 to Microsoft Edge will be included as part of all future Microsoft Edge updates. IE11 visual references, such as the IE11 icons on the Start Menu and taskbar, will be removed by the June 2023 Windows security update (“B” release) scheduled for June 13, 2023.”
For a more granular rundown on the updates released today, see the SANS Internet Storm Center roundup. If today’s updates cause any stability or usability issues in Windows, AskWoody.com will likely have the lowdown on that.
Please consider backing up your data and/or imaging your system before applying any updates. And feel free to sound off in the comments if you experience any problems as a result of these patches.
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Microsoft has released its final monthly batch of security updates for 2022, fixing more than four dozen security holes in its various Windows operating systems and related software. The most pressing patches include a zero-day in a Windows feature that tries to flag malicious files from the Web, a critical bug in PowerShell, and a dangerous flaw in Windows 11 systems that was detailed publicly prior to this week’s Patch Tuesday.
The security updates include patches for Azure, Microsoft Edge, Office, SharePoint Server, SysInternals, and the .NET framework. Six of the update bundles earned Microsoft’s most dire “critical” rating, meaning they fix vulnerabilities that malware or malcontents can use to remotely commandeer an unpatched Windows system — with little to no interaction on the part of the user.
The bug already seeing exploitation is CVE-2022-44698, which allows attackers to bypass the Windows SmartScreen security feature. The vulnerability allows attackers to craft documents that won’t get tagged with Microsoft’s “Mark of the Web,” despite being downloaded from untrusted sites.
“This means no Protected View for Microsoft Office documents, making it easier to get users to do sketchy things like execute malicious macros, said Greg Wiseman, product manager at security firm Rapid7. This is the second Mark of the Web flaw Microsoft has patched in as many months; both were first publicly detailed over the past two months on Twitter by security researcher Will Dormann.
Publicly disclosed (but not actively exploited for now) is CVE-2022-44710, which is an elevation of privilege flaw in the DirectX graphics component of Windows 11.
Another notable critical bug is CVE-2022-41076, a remote code execution flaw in PowerShell — a key component of Windows that makes it easier to automate system tasks and configurations.
Kevin Breen at Immersive Labs said while Microsoft doesn’t share much detail about CVE-2022-41076 apart from the designation ‘Exploitation More Likely,’ they also note that successful exploitation requires an attacker to take additional actions to prepare the target environment.
“What actions are required is not clear; however, we do know that exploitation requires an authenticated user level of access,” Breen said. “This combination suggests that the exploit requires a social engineering element, and would likely be seen in initial infections using attacks like MalDocs or LNK files.”
Speaking of malicious documents, Trend Micro’s Zero Day Initiative highlights CVE-2022-44713, a spoofing vulnerability in Outlook for Mac.
“We don’t often highlight spoofing bugs, but anytime you’re dealing with a spoofing bug in an e-mail client, you should take notice,” ZDI’s Dustin Childs wrote. “This vulnerability could allow an attacker to appear as a trusted user when they should not be. Now combine this with the SmartScreen Mark of the Web bypass and it’s not hard to come up with a scenario where you receive an e-mail that appears to be from your boss with an attachment entitled “Executive_Compensation.xlsx”. There aren’t many who wouldn’t open that file in that scenario.”
Microsoft also released guidance on reports that certain software drivers certified by Microsoft’s Windows Hardware Developer Program were being used maliciously in post-exploitation activity.
Three different companies reported evidence that malicious hackers were using these signed malicious driver files to lay the groundwork for ransomware deployment inside victim organizations. One of those companies, Sophos, published a blog post Tuesday detailing how the activity was tied to the Russian ransomware group Cuba, which has extorted an estimated $60 million from victims since 2019.
Of course, not all scary and pressing security threats are Microsoft-based. Also on Tuesday, Apple released a bevy of security updates to iOS, iPadOS, macOS, tvOS and Safari, including a patch for a newly discovered zero-day vulnerability that could lead to remote code execution.
Anyone responsible for maintaining Fortinet or Citrix remote access products probably needs to update, as both are dealing with active attacks on just-patched flaws.
For a closer look at the patches released by Microsoft today (indexed by severity and other metrics) check out the always-useful Patch Tuesday roundup from the SANS Internet Storm Center. And it’s not a bad idea to hold off updating for a few days until Microsoft works out any kinks in the updates: AskWoody.com usually has the lowdown on any patches that may be causing problems for Windows users.
As always, please consider backing up your system or at least your important documents and data before applying system updates. And if you run into any problems with these updates, please drop a note about it here in the comments.
Microsoft Corp. is investigating reports that attackers are exploiting two previously unknown vulnerabilities in Exchange Server, a technology many organizations rely on to send and receive email. Microsoft says it is expediting work on software patches to plug the security holes. In the meantime, it is urging a subset of Exchange customers to enable a setting that could help mitigate ongoing attacks.
In customer guidance released Thursday, Microsoft said it is investigating two reported zero-day flaws affecting Microsoft Exchange Server 2013, 2016, and 2019. CVE-2022-41040, is a Server-Side Request Forgery (SSRF) vulnerability that can enable an authenticated attacker to remotely trigger the second zero-day vulnerability — CVE-2022-41082 — which allows remote code execution (RCE) when PowerShell is accessible to the attacker.
Microsoft said Exchange Online has detections and mitigation in place to protect customers. Customers using on-premises Microsoft Exchange servers are urged to review the mitigations suggested in the security advisory, which Microsoft says should block the known attack patterns.
Vietnamese security firm GTSC on Thursday published a writeup on the two Exchange zero-day flaws, saying it first observed the attacks in early August being used to drop “webshells.” These web-based backdoors offer attackers an easy-to-use, password-protected hacking tool that can be accessed over the Internet from any browser.
“We detected webshells, mostly obfuscated, being dropped to Exchange servers,” GTSC wrote. “Using the user-agent, we detected that the attacker uses Antsword, an active Chinese-based opensource cross-platform website administration tool that supports webshell management. We suspect that these come from a Chinese attack group because the webshell codepage is 936, which is a Microsoft character encoding for simplified Chinese.”
GTSC’s advisory includes details about post-compromise activity and related malware, as well as steps it took to help customers respond to active compromises of their Exchange Server environment. But the company said it would withhold more technical details of the vulnerabilities for now.
In March 2021, hundreds of thousands of organizations worldwide had their email stolen and multiple backdoor webshells installed, all thanks to four zero-day vulnerabilities in Exchange Server.
Granted, the zero-day flaws that powered that debacle were far more critical than the two detailed this week, and there are no signs yet that exploit code has been publicly released (that will likely change soon). But part of what made last year’s Exchange Server mass hack so pervasive was that vulnerable organizations had little or no advance notice on what to look for before their Exchange Server environments were completely owned by multiple attackers.
Microsoft is quick to point out that these zero-day flaws require an attacker to have a valid username and password for an Exchange user, but this may not be such a tall order for the hackers behind these latest exploits against Exchange Server.
Steven Adair is president of Volexity, the Virginia-based cybersecurity firm that was among the first to sound the alarm about the Exchange zero-days targeted in the 2021 mass hack. Adair said GTSC’s writeup includes an Internet address used by the attackers that Volexity has tied with high confidence to a China-based hacking group that has recently been observed phishing Exchange users for their credentials.
In February 2022, Volexity warned that this same Chinese hacking group was behind the mass exploitation of a zero-day vulnerability in the Zimbra Collaboration Suite, which is a competitor to Microsoft Exchange that many enterprises use to manage email and other forms of messaging.
If your organization runs Exchange Server, please consider reviewing the Microsoft mitigations and the GTSC post-mortem on their investigations.
FreshRSS