Apple & Microsoft Patch Tuesday, July 2023 Edition

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.

Microsoft Patch Tuesday, July 2022 Edition

Microsoft today released updates to fix at least 86 security vulnerabilities in its Windows operating systems and other software, including a weakness in all supported versions of Windows that Microsoft warns is actively being exploited. The software giant also has made a controversial decision to put the brakes on a plan to block macros in Office documents downloaded from the Internet.

In February, security experts hailed Microsoft’s decision to block VBA macros in all documents downloaded from the Internet. The company said it would roll out the changes in stages between April and June 2022.

Macros have long been a trusted way for cybercrooks to trick people into running malicious code. Microsoft Office by default warns users that enabling macros in untrusted documents is a security risk, but those warnings can be easily disabled with the click of button. Under Microsoft’s plan, the new warnings provided no such way to enable the macros.

As Ars Technica veteran reporter Dan Goodin put it, “security professionals—some who have spent the past two decades watching clients and employees get infected with ransomware, wipers, and espionage with frustrating regularity—cheered the change.”

But last week, Microsoft abruptly changed course. As first reported by BleepingComputer, Redmond said it would roll back the changes based on feedback from users.

“While Microsoft has not shared the negative feedback that led to the rollback of this change, users have reported that they are unable to find the Unblock button to remove the Mark-of-the-Web from downloaded files, making it impossible to enable macros,” Bleeping’s Sergiu Gatlan wrote.

Microsoft later said the decision to roll back turning off macros by default was temporary, although it has not indicated when this important change might be made for good.

The zero-day Windows vulnerability already seeing active attacks is CVE-2022-22047, which is an elevation of privilege vulnerability in all supported versions of Windows. Trend Micro’s Zero Day Initiative notes that while this bug is listed as being under active attack, there’s no information from Microsoft on where or how widely it is being exploited.

“The vulnerability allows an attacker to execute code as SYSTEM, provided they can execute other code on the target,” ZDI’s Dustin Childs wrote. “Bugs of this type are typically paired with a code execution bug, usually a specially crafted Office or Adobe document, to take over a system. These attacks often rely on macros, which is why so many were disheartened to hear Microsoft’s delay in blocking all Office macros by default.”

Kevin Breen, director of cyber threat research at Immersive Labs, said CVE-2022-22047 is the kind of vulnerability that is typically seen abused after a target has already been compromised.

“Crucially, it allows the attacker to escalate their permissions from that of a normal user to the same permissions as the SYSTEM,” he said. “With this level of access, the attackers are able to disable local services such as Endpoint Detection and Security tools. With SYSTEM access they can also deploy tools like Mimikatz which can be used to recover even more admin and domain level accounts, spreading the threat quickly.”

After a brief reprieve from patching serious security problems in the Windows Print Spooler service, we are back to business as usual. July’s patch batch contains fixes for four separate elevation of privilege vulnerabilities in Windows Print Spooler, identified as CVE-2022-22022, CVE-2022-22041, CVE-2022-30206, and CVE-2022-30226. Experts at security firm Tenable note that these four flaws provide attackers with the ability to delete files or gain SYSTEM level privileges on a vulnerable system.

Roughly a third of the patches issued today involve weaknesses in Microsoft’s Azure Site Recovery offering. Other components seeing updates this month include Microsoft Defender for Endpoint; Microsoft Edge (Chromium-based); Office; Windows BitLocker; Windows Hyper-V; Skype for Business and Microsoft Lync; and Xbox.

Four of the flaws fixed this month address vulnerabilities Microsoft rates “critical,” meaning they could be used by malware or malcontents to assume remote control over unpatched Windows systems, usually without any help from users. CVE-2022-22029 and CVE-2022-22039 affect Network File System (NFS) servers, and CVE-2022-22038 affects the Remote Procedure Call (RPC) runtime.

“Although all three of these will be relatively tricky for attackers to exploit due to the amount of sustained data that needs to be transmitted, administrators should patch sooner rather than later,” said Greg Wiseman, product manager at Rapid7. “CVE-2022-30221 supposedly affects the Windows Graphics Component, though Microsoft’s FAQ indicates that exploitation requires users to access a malicious RDP server.”

Separately, Adobe today issued patches to address at least 27 vulnerabilities across multiple products, including Acrobat and Reader, Photoshop, RoboHelp, and Adobe Character Animator.

For a closer look at the patches released by Microsoft today and 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.