Rozena backdoor delivered by exploiting the Follina bug
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) |
Indicators of compromiseauto-extracted · verify before use · export allAll →
| Type | Indicator | Context |
|---|---|---|
| domain | duckdns.org | ches a reverse shell to the attacker’s machine (“microsofto.duckdns[.]org”), in this way the attacker can take full control of the |
Full article411 words · extracted from securityaffairs.com · click to collapse
Threat actors are exploiting the disclosed Follina Windows vulnerability to distribute the Rozena backdoor.
Fortinet FortiGuard Labs researchers observed a phishing campaign that is leveraging the recently disclosed Follina security vulnerability (CVE-2022-30190, CVSS score 7.8) to distribute the Rozena backdoor on Windows systems.
The Follina issue is a remote code execution vulnerability that resides in the Microsoft Windows Support Diagnostic Tool (MSDT).
The Rozena backdoor is able to inject a remote shell connection back to the attacker’s machine
The attack chain leverages a weaponized Office document that once clicked, it starts connecting to an external Discord CDN URL to download an HTML file (index.htm).
Then the HTML file invokes the msdt.exe tool with a PowerShell command which also invokes another web request to download the Rozena backdoor and save it as “Word.exe.”
“The PowerShell code will download one batch file cd.bat and start it with no window to hide itself. Then it invokes another web request to download Rozena and saves as “Word.exe” in the Windows Tasks folder.” reads the post published by Fortinet FortiGuard Labs.
“the attacker decided to distract the victim. The original file has no content besides an external link in oleObject. To keep the victim from noticing anything odd the batch file downloads another Word document, 1c9c88f811662007.docx with a lot of pictures in it. To make it seem more real, this document is saved in directory C:\\users\$env:USERNAME\Downloads, with a shorter name, 18562.docx.”
The main feature of the Rozena backdoor is to inject shellcode that launches a reverse shell to the attacker’s machine (“microsofto.duckdns[.]org”), in this way the attacker can take full control of the system.
Once the Rozena executable is run, it will create a process for a PowerShell command, experts pointed out that the decoded command has only one job to do, injecting the shellcode.
Additional technical details about the backdoor, including indicators of compromise (IoCs) are included in the analysis published by Fortinet.
“CVE-2022-30190 is a high-severity vulnerability that lets a malicious actor deliver malware though an MS Word document. Microsoft already released a patch for it on June 14, 2022. In this blog we showed how an attacker exploits Follina and included details of Rozena and the SGN ShellCode. Users should apply the patch immediately and also apply FortiGuard protection to avoid the threat.” concludes the report.
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Text extracted automatically; images, tables and formatting may be missing. Original: https://securityaffairs.com/133051/hacking/follina-bug-rozena-backdoor.html