Microsoft Acknowledges Zero-Day, Follina Office Vulnerability, Suggests Fix
Vulnerabilities mentionedAll →
| CVE | Vulnerability | CVSS | EPSS | Flags | Affected | Exposure | Published |
|---|---|---|---|---|---|---|---|
| CVE-2022-30190 | MSDT URL Protocol Remote Code Execution in Microsoft Windows (Follina) CVE-2022-30190 (Follina) is a remote code execution flaw in the Microsoft Windows Support Diagnostic Tool (MSDT) when MSDT is invoked through its ms-msdt URL protocol by a calling application such as Microsoft Word. Attackers trigger it by luring a user into opening a malicious document — typically a Word/RTF file whose link or remotely linked template launches the ms-msdt: URI with attacker-supplied commands — and CVSS 3.1 rates it 7.8 with a local attack vector and required user interaction. A successful exploit runs arbitrary code with the privileges of the calling application, allowing the attacker to install programs, view, change or delete data, or create new accounts in the user's context. Per the CISA data, affected platforms are Windows 7, 8.1 and RT 8.1, Windows 10 versions 1507 through 21H2, Windows 11 21H2, and Windows Server 2008 and 2012 — essentially any Windows installation that ships MSDT, with Office/Word as the common delivery vector. Exploitation is confirmed in the wild: Microsoft acknowledged it as an exploited zero-day, CISA added it to the KEV on 2022-06-14 with known ransomware use, EPSS puts the 30-day exploitation probability at 99.2% (99th percentile), and contemporaneous reporting also tied its use to espionage actors including APT28. Do: Apply Microsoft's security updates per vendor instructions (the fix shipped in the June 2022 Patch Tuesday releases for the affected Windows versions), as required by CISA's KEV. If patching must be delayed, follow Microsoft's documented mitigation to disable the MSDT URL protocol (remove or restrict the HKEY_CLASSES_ROOT\ms-msdt registry key) and enforce Office Protected View / block Word from fetching remote templates over the network. Hunt for exploitation by checking whether Office processes (WINWORD.exe) launch msdt.exe or sdiagnhost.exe, or whether ms-msdt: URIs are invoked unexpectedly. | 7.8 | 99% | KEV ransomware PoC |
| mass≈1 billion+ Windows devices (effectively the entire supported Windows installed base) |
Full article351 words · extracted from infosecurity-magazine.com · click to collapse
Microsoft released an advisory on Monday acknowledging the zero-day Office flaw dubbed ‘Follina’ and suggested a possible fix for it.
The document assigned the vulnerability the identifier CVE-2022-30190 and a rating of 7.8 out of 10 on the Common Vulnerability Scoring System (CVSS) on the basis that its exploitation may enable malicious actors to achieve code execution on affected systems.
“An attacker who successfully exploits this vulnerability can run arbitrary code with the privileges of the calling application,” Microsoft wrote.
From a technical standpoint, the malicious document used the Word remote template feature to download an HTML file from a remote server, which then used the MSDT (Microsoft Support Diagnostic Tool) URL Protocol to load some code and enable the execution of a PowerShell session.
“The attacker can then install programs, view, change, or delete data, or create new accounts in the context allowed by the user’s rights.”
In the advisory, Microsoft thanked crazyman, a member of the Shadow Chaser Group, for spotting and reporting the flaw back in April.
The vulnerability was then reportedly uploaded from an IP address in Belarus to the VirusTotal malware scanning service in May and analyzed by security researcher Kevin Beaumont (nao_sec), who named it “Follina” after the eponymous Italian village, as the malicious file reference (0438) was the same as the village’s area code.
Writing in the advisory, Microsoft also suggested a possible fix, which essentially consists of disabling the MSDT URL Protocol altogether.
“Disabling MSDT URL protocol prevents troubleshooters being launched as links including links throughout the operating system.”
In other words, if the calling application is a Microsoft Office application, by default, Microsoft Office will documents from the internet in ‘Protected View’ or ‘Application Guard for Office’, both of which stop the Follina attack.
“Troubleshooters can still be accessed using the Get Help application and in system settings as other or additional troubleshooters,” Microsoft added.
Further, the technology giant recommended users relying on Microsoft Defender Antivirus turn on cloud-delivered protection and automatic sample submission.
“These capabilities use artificial intelligence and machine learning to quickly identify and stop new and unknown threats.”
Text extracted automatically; images, tables and formatting may be missing. Original: https://www.infosecurity-magazine.com/news/microsoft-acknowledges-zero-day/