CVE-2025-34334: fax server Command Injection — Exploit

Description

AudioCodes Fax Server and Auto-Attendant IVR appliances versions up to and including 2.6.23 are vulnerable to an authenticated command injection in the fax test functionality implemented by AudioCodes_files/TestFax.php. When a fax "send" test is requested, the application builds a faxsender command line using attacker-supplied parameters and passes it to GlobalUtils::RunBatchFile without proper validation or shell-argument sanitization. The resulting batch file is written into a temporary run directory and then executed via a backend service that runs as NT AUTHORITY\\SYSTEM. An authenticated attacker with access to the fax test interface can craft parameter values that inject additional shell commands into the generated batch file, leading to arbitrary command execution with SYSTEM privileges. In addition, because the generated batch files reside in a location with overly permissive file system permissions, a local low-privilege user on the server can modify pending batch files to achieve the same elevation.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-78 OS Command Injection

Affected Products

Vendor	Product	Versions
audiocodes	fax_server	< 2.6.23
audiocodes	interactive_voice_response	< 2.6.23

References

Exploits

https://pierrekim.github.io/advisories/2025-audiocodes-fax-ivr.txt https://pierrekim.github.io/blog/2025-11-20-audiocodes-fax-ivr-8-vulnerabilities.html

Other References

https://www.audiocodes.com/media/g1in2u2o/0548-product-notice-end-of-service-for-audiocodes-auto-attendant-ivr-solution.pdf https://www.vulncheck.com/advisories/audiocodes-fax-ivr-appliance-authenticated-command-injection-via-testfax-and-lpe

Frequently Asked Questions

What is CVE-2025-34334? +

AudioCodes Fax Server and Auto-Attendant IVR appliances versions up to and including 2.6.23 are vulnerable to an authenticated command injection in the fax test functionality implemented by AudioCodes_files/TestFax.php. When a fax "send" test is requested, the application builds a faxsender command line using attacker-supplied parameters and passes it to GlobalUtils::RunBatchFile without proper validation or shell-argument sanitization. The resulting batch file is written into a temporary run directory and then executed via a backend service that runs as NT AUTHORITY\\SYSTEM. An authenticated attacker with access to the fax test interface can craft parameter values that inject additional shell commands into the generated batch file, leading to arbitrary command execution with SYSTEM privileges. In addition, because the generated batch files reside in a location with overly permissive file system permissions, a local low-privilege user on the server can modify pending batch files to achieve the same elevation. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2025-34334? +

CVE-2025-34334 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-34334? +

CVE-2025-34334 affects products from audiocodes, specifically: fax_server, interactive_voice_response. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-34334? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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