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If only Patch Tuesdays came around infrequently — like total solar eclipse rare — instead of just creeping up on us each month like The Man in the Moon. Although to be fair, it would be tough for Microsoft to eclipse the number of vulnerabilities fixed in this month’s patch batch — a record 147 flaws in Windows and related software.
Yes, you read that right. Microsoft today released updates to address 147 security holes in Windows, Office, Azure, .NET Framework, Visual Studio, SQL Server, DNS Server, Windows Defender, Bitlocker, and Windows Secure Boot.
“This is the largest release from Microsoft this year and the largest since at least 2017,” said Dustin Childs, from Trend Micro’s Zero Day Initiative (ZDI). “As far as I can tell, it’s the largest Patch Tuesday release from Microsoft of all time.”
Tempering the sheer volume of this month’s patches is the middling severity of many of the bugs. Only three of April’s vulnerabilities earned Microsoft’s most-dire “critical” rating, meaning they can be abused by malware or malcontents to take remote control over unpatched systems with no help from users.
Most of the flaws that Microsoft deems “more likely to be exploited” this month are marked as “important,” which usually involve bugs that require a bit more user interaction (social engineering) but which nevertheless can result in system security bypass, compromise, and the theft of critical assets.
Ben McCarthy, lead cyber security engineer at Immersive Labs called attention to CVE-2024-20670, an Outlook for Windows spoofing vulnerability described as being easy to exploit. It involves convincing a user to click on a malicious link in an email, which can then steal the user’s password hash and authenticate as the user in another Microsoft service.
Another interesting bug McCarthy pointed to is CVE-2024-29063, which involves hard-coded credentials in Azure’s search backend infrastructure that could be gleaned by taking advantage of Azure AI search.
“This along with many other AI attacks in recent news shows a potential new attack surface that we are just learning how to mitigate against,” McCarthy said. “Microsoft has updated their backend and notified any customers who have been affected by the credential leakage.”
CVE-2024-29988 is a weakness that allows attackers to bypass Windows SmartScreen, a technology Microsoft designed to provide additional protections for end users against phishing and malware attacks. Childs said one of ZDI’s researchers found this vulnerability being exploited in the wild, although Microsoft doesn’t currently list CVE-2024-29988 as being exploited.
“I would treat this as in the wild until Microsoft clarifies,” Childs said. “The bug itself acts much like CVE-2024-21412 – a [zero-day threat from February] that bypassed the Mark of the Web feature and allows malware to execute on a target system. Threat actors are sending exploits in a zipped file to evade EDR/NDR detection and then using this bug (and others) to bypass Mark of the Web.”
Update, 7:46 p.m. ET: A previous version of this story said there were no zero-day vulnerabilities fixed this month. BleepingComputer reports that Microsoft has since confirmed that there are actually two zero-days. One is the flaw Childs just mentioned (CVE-2024-21412), and the other is CVE-2024-26234, described as a “proxy driver spoofing” weakness.
Satnam Narang at Tenable notes that this month’s release includes fixes for two dozen flaws in Windows Secure Boot, the majority of which are considered “Exploitation Less Likely” according to Microsoft.
“However, the last time Microsoft patched a flaw in Windows Secure Boot in May 2023 had a notable impact as it was exploited in the wild and linked to the BlackLotus UEFI bootkit, which was sold on dark web forums for $5,000,” Narang said. “BlackLotus can bypass functionality called secure boot, which is designed to block malware from being able to load when booting up. While none of these Secure Boot vulnerabilities addressed this month were exploited in the wild, they serve as a reminder that flaws in Secure Boot persist, and we could see more malicious activity related to Secure Boot in the future.”
For links to individual security advisories indexed by severity, check out ZDI’s blog and the Patch Tuesday post from the SANS Internet Storm Center. Please consider backing up your data or your drive before updating, and drop a note in the comments here if you experience any issues applying these fixes.
Adobe today released nine patches tackling at least two dozen vulnerabilities in a range of software products, including Adobe After Effects, Photoshop, Commerce, InDesign, Experience Manager, Media Encoder, Bridge, Illustrator, and Adobe Animate.
KrebsOnSecurity needs to correct the record on a point mentioned at the end of March’s “Fat Patch Tuesday” post, which looked at new AI capabilities built into Adobe Acrobat that are turned on by default. Adobe has since clarified that its apps won’t use AI to auto-scan your documents, as the original language in its FAQ suggested.
“In practice, no document scanning or analysis occurs unless a user actively engages with the AI features by agreeing to the terms, opening a document, and selecting the AI Assistant or generative summary buttons for that specific document,” Adobe said earlier this month.
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Apple and Microsoft recently released software updates to fix dozens of security holes in their operating systems. Microsoft today patched at least 60 vulnerabilities in its Windows OS. Meanwhile, Apple’s new macOS Sonoma addresses at least 68 security weaknesses, and its latest update for iOS fixes two zero-day flaws.
Last week, Apple pushed out an urgent software update to its flagship iOS platform, warning that there were at least two zero-day exploits for vulnerabilities being used in the wild (CVE-2024-23225 and CVE-2024-23296). The security updates are available in iOS 17.4, iPadOS 17.4, and iOS 16.7.6.
Apple’s macOS Sonoma 14.4 Security Update addresses dozens of security issues. Jason Kitka, chief information security officer at Automox, said the vulnerabilities patched in this update often stem from memory safety issues, a concern that has led to a broader industry conversation about the adoption of memory-safe programming languages [full disclosure: Automox is an advertiser on this site].
On Feb. 26, 2024, the Biden administration issued a report that calls for greater adoption of memory-safe programming languages. On Mar. 4, 2024, Google published Secure by Design, which lays out the company’s perspective on memory safety risks.
Mercifully, there do not appear to be any zero-day threats hounding Windows users this month (at least not yet). Satnam Narang, senior staff research engineer at Tenable, notes that of the 60 CVEs in this month’s Patch Tuesday release, only six are considered “more likely to be exploited” according to Microsoft.
Those more likely to be exploited bugs are mostly “elevation of privilege vulnerabilities” including CVE-2024-26182 (Windows Kernel), CVE-2024-26170 (Windows Composite Image File System (CimFS), CVE-2024-21437 (Windows Graphics Component), and CVE-2024-21433 (Windows Print Spooler).
Narang highlighted CVE-2024-21390 as a particularly interesting vulnerability in this month’s Patch Tuesday release, which is an elevation of privilege flaw in Microsoft Authenticator, the software giant’s app for multi-factor authentication. Narang said a prerequisite for an attacker to exploit this flaw is to already have a presence on the device either through malware or a malicious application.
“If a victim has closed and re-opened the Microsoft Authenticator app, an attacker could obtain multi-factor authentication codes and modify or delete accounts from the app,” Narang said. “Having access to a target device is bad enough as they can monitor keystrokes, steal data and redirect users to phishing websites, but if the goal is to remain stealth, they could maintain this access and steal multi-factor authentication codes in order to login to sensitive accounts, steal data or hijack the accounts altogether by changing passwords and replacing the multi-factor authentication device, effectively locking the user out of their accounts.”
CVE-2024-21334 earned a CVSS (danger) score of 9.8 (10 is the worst), and it concerns a weakness in Open Management Infrastructure (OMI), a Linux-based cloud infrastructure in Microsoft Azure. Microsoft says attackers could connect to OMI instances over the Internet without authentication, and then send specially crafted data packets to gain remote code execution on the host device.
CVE-2024-21435 is a CVSS 8.8 vulnerability in Windows OLE, which acts as a kind of backbone for a great deal of communication between applications that people use every day on Windows, said Ben McCarthy, lead cybersecurity engineer at Immersive Labs.
“With this vulnerability, there is an exploit that allows remote code execution, the attacker needs to trick a user into opening a document, this document will exploit the OLE engine to download a malicious DLL to gain code execution on the system,” Breen explained. “The attack complexity has been described as low meaning there is less of a barrier to entry for attackers.”
A full list of the vulnerabilities addressed by Microsoft this month is available at the SANS Internet Storm Center, which breaks down the updates by severity and urgency.
Finally, Adobe today issued security updates that fix dozens of security holes in a wide range of products, including Adobe Experience Manager, Adobe Premiere Pro, ColdFusion 2023 and 2021, Adobe Bridge, Lightroom, and Adobe Animate. Adobe said it is not aware of active exploitation against any of the flaws.
By the way, Adobe recently enrolled all of its Acrobat users into a “new generative AI feature” that scans the contents of your PDFs so that its new “AI Assistant” can “understand your questions and provide responses based on the content of your PDF file.” Adobe provides instructions on how to disable the AI features and opt out here.
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One frustrating aspect of email phishing is the frequency with which scammers fall back on tried-and-true methods that really have no business working these days. Like attaching a phishing email to a traditional, clean email message, or leveraging link redirects on LinkedIn, or abusing an encoding method that makes it easy to disguise booby-trapped Microsoft Windows files as relatively harmless documents.
KrebsOnSecurity recently heard from a reader who was puzzled over an email he’d just received saying he needed to review and complete a supplied W-9 tax form. The missive was made to appear as if it were part of a mailbox delivery report from Microsoft 365 about messages that had failed to deliver.
The reader, who asked to remain anonymous, said the phishing message contained an attachment that appeared to have a file extension of “.pdf,” but something about it seemed off. For example, when he downloaded and tried to rename the file, the right arrow key on the keyboard moved his cursor to the left, and vice versa.
The file included in this phishing scam uses what’s known as a “right-to-left override” or RLO character. RLO is a special character within unicode — an encoding system that allows computers to exchange information regardless of the language used — that supports languages written from right to left, such as Arabic and Hebrew.
Look carefully at the screenshot below and you’ll notice that while Microsoft Windows says the file attached to the phishing message is named “lme.pdf,” the full filename is “fdp.eml” spelled backwards. In essence, this is a .eml file — an electronic mail format or email saved in plain text — masquerading as a .PDF file.
“The email came through Microsoft Office 365 with all the detections turned on and was not caught,” the reader continued. “When the same email is sent through Mimecast, Mimecast is smart enough to detect the encoding and it renames the attachment to ‘___fdp.eml.’ One would think Microsoft would have had plenty of time by now to address this.”
Indeed, KrebsOnSecurity first covered RLO-based phishing attacks back in 2011, and even then it wasn’t a new trick.
Opening the .eml file generates a rendering of a webpage that mimics an alert from Microsoft about wayward messages awaiting restoration to your inbox. Clicking on the “Restore Messages” link there bounces you through an open redirect on LinkedIn before forwarding to the phishing webpage.
As noted here last year, scammers have long taken advantage of a marketing feature on the business networking site which lets them create a LinkedIn.com link that bounces your browser to other websites, such as phishing pages that mimic top online brands (but chiefly Linkedin’s parent firm Microsoft).
The landing page after the LinkedIn redirect displays what appears to be an Office 365 login page, which is naturally a phishing website made to look like an official Microsoft Office property.
In summary, this phishing scam uses an old RLO trick to fool Microsoft Windows into thinking the attached file is something else, and when clicked the link uses an open redirect on a Microsoft-owned website (LinkedIn) to send people to a phishing page that spoofs Microsoft and tries to steal customer email credentials.
According to the latest figures from Check Point Software, Microsoft was by far the most impersonated brand for phishing scams in the second quarter of 2023, accounting for nearly 30 percent of all brand phishing attempts.
An unsolicited message that arrives with one of these .eml files as an attachment is more than likely to be a phishing lure. The best advice to sidestep phishing scams is to avoid clicking on links that arrive unbidden in emails, text messages and other mediums. Most phishing scams invoke a temporal element that warns of dire consequences should you fail to respond or act quickly.
If you’re unsure whether a message is legitimate, take a deep breath and visit the site or service in question manually — ideally, using a browser bookmark to avoid potential typosquatting sites.
The U.S. Federal Bureau of Investigation (FBI) this week seized 13 domain names connected to “booter” services that let paying customers launch crippling distributed denial-of-service (DDoS) attacks. Ten of the domains are reincarnations of DDoS-for-hire services the FBI seized in December 2022, when it charged six U.S. men with computer crimes for allegedly operating booters.
Booter services are advertised through a variety of methods, including Dark Web forums, chat platforms and even youtube.com. They accept payment via PayPal, Google Wallet, and/or cryptocurrencies, and subscriptions can range in price from just a few dollars to several hundred per month. The services are generally priced according to the volume of traffic to be hurled at the target, the duration of each attack, and the number of concurrent attacks allowed.
The websites that saw their homepages replaced with seizure notices from the FBI this week include booter services like cyberstress[.]org and exoticbooter[.]com, which the feds say were used to launch millions of attacks against millions of victims.
“School districts, universities, financial institutions and government websites are among the victims who have been targeted in attacks launched by booter services,” federal prosecutors in Los Angeles said in a statement.
Purveyors of booters or “stressers” claim they are not responsible for how customers use their services, and that they aren’t breaking the law because — like most security tools — these services can be used for good or bad purposes. Most booter sites employ wordy “terms of use” agreements that require customers to agree they will only stress-test their own networks — and that they won’t use the service to attack others.
But the DOJ says these disclaimers usually ignore the fact that most booter services are heavily reliant on constantly scanning the Internet to commandeer misconfigured devices that are critical for maximizing the size and impact of DDoS attacks. What’s more, none of the services seized by the government required users to demonstrate that they own the Internet addresses being stress-tested, something a legitimate testing service would insist upon.
This is the third in a series of U.S. and international law enforcement actions targeting booter services. In December 2022, the feds seized four-dozen booter domains and charged six U.S. men with computer crimes related to their alleged ownership of the popular DDoS-for-hire services. In December 2018, the feds targeted 15 booter sites, and three booter store defendants who later pleaded guilty.
While the FBI’s repeated seizing of booter domains may seem like an endless game of virtual Whac-a-Mole, continuously taking these services offline imposes high enough costs for the operators that some of them will quit the business altogether, says Richard Clayton, director of Cambridge University’s Cybercrime Centre.
In 2020, Clayton and others published “Cybercrime is Mostly Boring,” an academic study on the quality and types of work needed to build, maintain and defend illicit enterprises that make up a large portion of the cybercrime-as-a-service market. The study found that operating a booter service effectively requires a mind-numbing amount of constant, tedious work that tends to produce high burnout rates for booter service operators — even when the service is operating efficiently and profitably.
For example, running an effective booter service requires a substantial amount of administrative work and maintenance, much of which involves constantly scanning for, commandeering and managing large collections of remote systems that can be used to amplify online attacks, Clayton said. On top of that, building brand recognition and customer loyalty takes time.
“If you’re running a booter and someone keeps taking your domain or hosting away, you have to then go through doing the same boring work all over again,” Clayton told KrebsOnSecurity. “One of the guys the FBI arrested in December [2022] spent six months moaning that he lost his servers, and could people please lend him some money to get it started again.”
In a statement released Wednesday, prosecutors in Los Angeles said four of the six men charged last year for running booter services have since pleaded guilty. However, at least one of the defendants from the 2022 booter bust-up — John M. Dobbs, 32, of Honolulu, HI — has pleaded not guilty and is signaling he intends to take his case to trial.
The FBI seizure notice that replaced the homepages of several booter services this week.
Dobbs is a computer science graduate student who for the past decade openly ran IPStresser[.]com, a popular and powerful attack-for-hire service that he registered with the state of Hawaii using his real name and address. Likewise, the domain was registered in Dobbs’s name and hometown in Pennsylvania. Prosecutors say Dobbs’ service attracted more than two million registered users, and was responsible for launching a staggering 30 million distinct DDoS attacks.
Many accused stresser site operators have pleaded guilty over the years after being hit with federal criminal charges. But the government’s core claim — that operating a booter site is a violation of U.S. computer crime laws — wasn’t properly tested in the courts until September 2021.
That was when a jury handed down a guilty verdict against Matthew Gatrel, a then 32-year-old St. Charles, Ill. man charged in the government’s first 2018 mass booter bust-up. Despite admitting to FBI agents that he ran two booter services (and turning over plenty of incriminating evidence in the process), Gatrel opted to take his case to trial, defended the entire time by court-appointed attorneys.
Gatrel was convicted on all three charges of violating the Computer Fraud and Abuse Act, including conspiracy to commit unauthorized impairment of a protected computer, conspiracy to commit wire fraud, and unauthorized impairment of a protected computer. He was sentenced to two years in prison.
A copy of the FBI’s booter seizure warrant is here (PDF). According to the DOJ, the defendants who pleaded guilty to operating booter sites include:
–Jeremiah Sam Evans Miller, aka “John The Dev,” 23, of San Antonio, Texas, who pleaded guilty on April 6 to conspiracy and violating the computer fraud and abuse act related to the operation of a booter service named RoyalStresser[.]com (formerly known as Supremesecurityteam[.]com);
–Angel Manuel Colon Jr., aka “Anonghost720” and “Anonghost1337,” 37, of Belleview, Florida, who pleaded guilty on February 13 to conspiracy and violating the computer fraud and abuse act related to the operation of a booter service named SecurityTeam[.]io;
–Shamar Shattock, 19, of Margate, Florida, who pleaded guilty on March 22 to conspiracy to violate the computer fraud and abuse act related to the operation of a booter service known as Astrostress[.]com;
–Cory Anthony Palmer, 23, of Lauderhill, Florida, who pleaded guilty on February 16 to conspiracy to violate the computer fraud and abuse act related to the operation of a booter service known as Booter[.]sx.
All four defendants are scheduled to be sentenced this summer.
The booter domains seized by the FBI this week include:
cyberstress[.]org
exoticbooter[.]com
layerstress[.]net
orbitalstress[.]xyz
redstresser[.]io
silentstress[.]wtf
sunstresser[.]net
silent[.]to
mythicalstress[.]net
dreams-stresser[.]org
stresserbest[.]io
stresserus[.]io
quantum-stress[.]org
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