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Microsoft Patch Tuesday, May 2023 Edition
Microsoft today released software updates to fix at least four dozen security holes in its Windows operating systems and other software, including patches for two zero-day vulnerabilities that are already being exploited in active attacks.
Microsoft today released software updates to fix at least four dozen security holes in its Windows operating systems and other software, including patches for two zero-day vulnerabilities that are already being exploited in active attacks.
First up in May’s zero-day flaws is CVE-2023-29336, which is an “elevation of privilege” weakness in Windows which has a low attack complexity, requires low privileges, and no user interaction. However, as the SANS Internet Storm Center points out, the attack vector for this bug is local.
“Local Privilege escalation vulnerabilities are a key part of attackers’ objectives,” said Kevin Breen, director of cyber threat research at Immersive Labs. “Once they gain initial access they will seek administrative or SYSTEM-level permissions. This can allow the attacker to disable security tooling and deploy more attacker tools like Mimikatz that lets them move across the network and gain persistence.”
The zero-day patch that has received the most attention so far is CVE-2023-24932, which is a Secure Boot Security Feature Bypass flaw that is being actively exploited by “bootkit” malware known as “BlackLotus.” A bootkit is dangerous because it allows the attacker to load malicious software before the operating system even starts up.
According to Microsoft’s advisory, an attacker would need physical access or administrative rights to a target device, and could then install an affected boot policy. Microsoft gives this flaw a CVSS score of just 6.7, rating it as “Important.”
Adam Barnett, lead software engineer at Rapid7, said CVE-2023-24932 deserves a considerably higher threat score.
“Microsoft warns that an attacker who already has Administrator access to an unpatched asset could exploit CVE-2023-24932 without necessarily having physical access,” Barnett said. “Therefore, the relatively low CVSSv3 base score of 6.7 isn’t necessarily a reliable metric in this case.”
Barnett said Microsoft has provided a supplementary guidance article specifically calling out the threat posed by BlackLotus malware, which loads ahead of the operating system on compromised assets, and provides attackers with an array of powerful evasion, persistence, and Command & Control (C2) techniques, including deploying malicious kernel drivers, and disabling Microsoft Defender or Bitlocker.
“Administrators should be aware that additional actions are required beyond simply applying the patches,” Barnett advised. “The patch enables the configuration options necessary for protection, but administrators must apply changes to UEFI config after patching. The attack surface is not limited to physical assets, either; Windows assets running on some VMs, including Azure assets with Secure Boot enabled, also require these extra remediation steps for protection. Rapid7 has noted in the past that enabling Secure Boot is a foundational protection against driver-based attacks. Defenders ignore this vulnerability at their peril.”
In addition to the two zero-days fixed this month, Microsoft also patched five remote code execution (RCE) flaws in Windows, two of which have notably high CVSS scores.
CVE-2023-24941 affects the Windows Network File System, and can be exploited over the network by making an unauthenticated, specially crafted request. Microsoft’s advisory also includes mitigation advice. The CVSS for this vulnerability is 9.8 – the highest of all the flaws addressed this month.
Meanwhile, CVE-2023-28283 is a critical bug in the Windows Lightweight Directory Access Protocol (LDAP) that allows an unauthenticated attacker to execute malicious code on the vulnerable device. The CVSS for this vulnerability is 8.1, but Microsoft says exploiting the flaw may be tricky and unreliable for attackers.
Another vulnerability patched this month that was disclosed publicly before today (but not yet seen exploited in the wild) is CVE-2023-29325, a weakness in Microsoft Outlook and Explorer that can be exploited by attackers to remotely install malware. Microsoft says this vulnerability can be exploited merely by viewing a specially-crafted email in the Outlook Preview Pane.
“To help protect against this vulnerability, we recommend users read email messages in plain text format,” Microsoft’s writeup on CVE-2023-29325 advises.
“If an attacker were able to exploit this vulnerability, they would gain remote access to the victim’s account, where they could deploy additional malware,” Immersive’s Breen said. “This kind of exploit will be highly sought after by e-crime and ransomware groups where, if successfully weaponized, could be used to target hundreds of organizations with very little effort.”
For more details on the updates released today, check out roundups by Action1, Automox and Qualys, 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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Hello everyone! This episode will be about Microsoft Patch Tuesday for May 2023, including vulnerabilities that were added between April and May Patch Tuesdays. As usual, I use my open source Vulristics project to analyse and prioritize vulnerabilities. I took the comments about the vulnerabilities from the Qualys, Tenable, Rapid7, ZDI Patch Tuesday reviews. It’s been a […]
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Microsoft has rolled out Patch Tuesday updates for May 2023 to address 38 security flaws, including one zero-day bug that it said is being actively exploited in the wild. Trend Micro's Zero Day Initiative (ZDI) said the volume is the lowest since August 2021, although it pointed out that "this number is expected to rise in the coming months." Of the 38 vulnerabilities, six are rated Critical and
Microsoft has rolled out Patch Tuesday updates for May 2023 to address 38 security flaws, including one zero-day bug that it said is being actively exploited in the wild. Trend Micro's Zero Day Initiative (ZDI) said the volume is the lowest since August 2021, although it pointed out that "this number is expected to rise in the coming months." Of the 38 vulnerabilities, six are rated Critical and
Microsoft has rolled out Patch Tuesday updates for May 2023 to address 38 security flaws, including one zero-day bug that it said is being actively exploited in the wild. Trend Micro's Zero Day Initiative (ZDI) said the volume is the lowest since August 2021, although it pointed out that "this number is expected to rise in the coming months." Of the 38 vulnerabilities, six are rated Critical and
Categories: Exploits and vulnerabilities Categories: News Tags: Microsoft Tags: CVE-2023-29336 Tags: CVE-2023-24932 Tags: bootkit Tags: CVE-2023-29325 Tags: Outlook Tags: preview Tags: CVE-2023-24941 Tags: Apple Tags: Cisco Tags: Google Tags: Android Tags: VMWare Tags: SAP Tags: Mozilla Microsoft's Patch Tuesday round up for May 2023 includes patches for three zero-day vulnerabilities and one critical remote code execution vulnerability (Read more...) The post Update now! May 2023 Patch Tuesday tackles three zero-days appeared first on Malwarebytes Labs.
Windows OLE Remote Code Execution Vulnerability
Windows Network File System Remote Code Execution Vulnerability
Windows Lightweight Directory Access Protocol (LDAP) Remote Code Execution Vulnerability
One of the vulnerabilities is being actively exploited in the wild, according to Microsoft, the fourth month in a row in which this is the case.
One of the vulnerabilities is being actively exploited in the wild, according to Microsoft, the fourth month in a row in which this is the case.
One of the vulnerabilities is being actively exploited in the wild, according to Microsoft, the fourth month in a row in which this is the case.
One of the vulnerabilities is being actively exploited in the wild, according to Microsoft, the fourth month in a row in which this is the case.
Mitigation refers to a setting, common configuration, or general best-practice, existing in a default state, that could reduce the severity of exploitation of a vulnerability. The following mitigating factors might be helpful in your situation: This vulnerability is not exploitable in NFSV2.0 or NFSV3.0. Prior to updating your version of Windows that protects against this vulnerability, you can mitigate an attack by disabling NFSV4.1. This could adversely affect your ecosystem and should only be used as a temporary mitigation. **Warning** You should NOT apply this mitigation unless you have installed the May 2022 Windows security updates. Those updates address CVE-2022-26937 which is a Critical vulnerability in NFSV2.0 and NFSV3.0. The following PowerShell command will disable those versions: PS C:\Set-NfsServerConfiguration -EnableNFSV4 $false After running the command, you will need to restart NFS server or reboot the machine. To restart NFS server, start a **cmd** window with...
**What kind of security feature could be bypassed by successfully exploiting this vulnerability?** An attacker who successfully exploited this vulnerability could bypass Secure Boot.
Summary Summary Today, Microsoft is releasing CVE-2023-24932, and associated configuration guidance, to address a Secure Boot bypass vulnerability used by the BlackLotus bootkit to exploit CVE-2022-21894. Customers will need to closely follow the configuration guidance to fully protect against this vulnerability. This vulnerability allows an attacker to execute self-signed code at the Unified Extensible Firmware Interface (UEFI) level while Secure Boot is enabled.
**According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?** Successful exploitation of this vulnerability requires an attacker to win a race condition.
**What privileges could be gained by an attacker who successfully exploited this vulnerability?** An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.
**Is the Preview Pane an attack vector for this vulnerability?** Yes, the Preview Pane is an attack vector.