CISA adds UnRAR and Windows flaws to Known Exploited Vulnerabilities Catalog

RARLAB's UnRAR command-line decompression tool on Linux and UNIX, in versions before 6.12, contains a directory traversal flaw (CWE-22, with symlink-based path confusion per CWE-59) that lets a crafted RAR archive write files to arbitrary filesystem locations during an extract/unpack operation. It is triggered whenever an application passes an attacker-supplied archive to unrar, most prominently Zimbra Collaboration Suite, which unpacked RAR attachments from incoming email, enabling pre-authentication attacks against webmail tracked separately as CVE-2022-41352. By planting files at chosen paths — for example writing an SSH key to ~/.ssh/authorized_keys or dropping a web shell under a web root — an attacker can escalate an arbitrary file write into code execution on the server, requiring no privileges or user interaction per the CVSS vector. Only the Linux/UNIX UnRAR utility is affected; WinRAR and RAR for Android are not. The flaw is under active exploitation: CISA added it to the Known Exploited Vulnerabilities catalog on 2022-08-09 with known ransomware use, public PoCs exist, and EPSS estimates a ~99% probability of exploitation within 30 days.

Do: Upgrade UnRAR to 6.12 or later on all Linux and UNIX systems and apply Debian's patched unrar package; Zimbra administrators should apply Zimbra's released security patches, which ship the fixed UnRAR. As an interim mitigation, restrict or monitor services that automatically extract RAR archives from untrusted sources, and hunt for indicators such as unexpected ~/.ssh/authorized_keys entries, planted symlinks, or web shells under web roots. Because the flaw is on CISA's KEV list with known ransomware use, treat patching as time-critical.

CVE-2022-34713, commonly referred to as 'DogWalk,' is a remote code execution vulnerability in the Microsoft Windows Support Diagnostic Tool (MSDT), patched in Microsoft's August 2022 Patch Tuesday release. The flaw requires user interaction: a user who engages with attacker-supplied content that invokes MSDT can allow the attacker's file operations to run in the context of the logged-on user, yielding high-impact code execution (confidentiality, integrity, and availability all rated high in the CVSS vector). Affected products span essentially the entire supported Windows installed base at the time: Windows 7, 8.1, RT 8.1, Windows 10 (1507 through 21H2), Windows 11 21H2, and Windows Server 2008 and 2012. The vulnerability was confirmed by Microsoft as an actively exploited zero-day in August 2022 and was added to CISA's Known Exploited Vulnerabilities catalog on 2022-08-09, with a required action to apply vendor updates. EPSS assigns it a 67.8% probability of exploitation within 30 days (99th percentile), consistent with in-the-wild use.

Do: Apply the August 2022 (or later) Windows security updates on all affected Windows 7, 8.1, RT 8.1, 10 (1507–21H2), 11 21H2, Server 2008, and Server 2012 systems per vendor instructions, prioritizing user-facing workstations where exploitation depends on user interaction. Given the KEV listing, federal and high-value environments should verify patch status immediately and hunt for suspicious MSDT/diagnostic-tool invocations. No public PoC is known, but treat any unpatched system as exposed given confirmed in-the-wild exploitation.