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CriticalPublic exploit

Arbitrary PHP Code Execution via Language Cookie in Discuz!ML 3.2-3.4

IdentifiersCVE-2019-13956CWE-94· Improper Control of Generation of…

Discuz!ML versions 3.2 through 3.4 are vulnerable to arbitrary PHP code execution due to improper handling of the language cookie. An attacker can modify the language cookie value to inject and execute arbitrary PHP code on the server. For example, by setting the cookie 4gH4_0df5_language to a value such as en'.phpinfo().';, the attacker can trigger execution of the phpinfo() function, demonstrating code execution. The vulnerability is due to insufficient sanitization of user-supplied input in the language cookie, which is used in a PHP eval context or similar dynamic code inclusion.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows remote attackers to execute arbitrary PHP code on the server, leading to full compromise of the affected application and potentially the underlying server. Attackers can gain unauthorized access, exfiltrate data, or use the server as a pivot point for further attacks.

Mitigation

If you can’t patch tonight, do this now.

As an immediate mitigation, implement strict input validation and sanitization on the language cookie value. Deploy web application firewalls (WAF) to detect and block malicious payloads in cookies. Disable or restrict the use of dynamic code execution functions in the application configuration if possible.

Remediation

Patch, then assume compromise.

Upgrade Discuz!ML to a version where this vulnerability is patched. Ensure that all user-supplied input, especially cookies, are properly sanitized and validated before being used in any code execution or inclusion context. Avoid using dynamic code execution functions such as eval or include with user-controlled data.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

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VendorProductType
CodersclubDiscuz!Mlapplication

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Threat actor evidence

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Associated malware1

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Detection signatures

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Vendor-by-vendor mapping

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