CVE-2025-34061
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BaseFortify

Publication date: 2025-07-03

Last updated on: 2025-07-08

Assigner: VulnCheck

Description
A backdoor in PHPStudy versions 2016 through 2018 allows unauthenticated remote attackers to execute arbitrary PHP code on affected installations. The backdoor listens for base64-encoded PHP payloads in the Accept-Charset HTTP header of incoming requests, decodes and executes the payload without proper validation. This leads to remote code execution as the web server user, compromising the affected system.
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Meta Information
Published
2025-07-03
Last Modified
2025-07-08
Generated
2026-05-07
AI Q&A
2025-07-03
EPSS Evaluated
2026-05-05
NVD
EUVD
Affected Vendors & Products
Currently, no data is known.
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-94 The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability is a backdoor in PHPStudy versions 2016 through 2018 that allows unauthenticated remote attackers to execute arbitrary PHP code on affected systems. The backdoor listens for base64-encoded PHP code sent in the Accept-Charset HTTP header of incoming requests, decodes it, and executes it without proper validation. This enables attackers to run any PHP code remotely as the web server user, compromising the system. [1]


How can this vulnerability impact me? :

The vulnerability allows attackers to execute arbitrary PHP code remotely without authentication, which can lead to full compromise of the affected system. Attackers can run malicious code, potentially gaining control over the server, accessing sensitive data, modifying or deleting files, and using the server for further attacks. [1]


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by sending a GET request to the target URI (default /l.php) with a random alphanumeric string encoded in the Accept-Charset HTTP header. If the response body contains this string, the backdoor is confirmed present. For example, using curl: curl -H "Accept-Charset: <base64-encoded-random-string>" http://target/l.php and checking if the response contains the decoded string. [1]


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation steps include disabling or uninstalling affected PHPStudy versions (2016 through 2018), restricting access to the vulnerable service, and applying any available patches or updates from the vendor. Additionally, monitoring logs for suspicious Accept-Charset headers and blocking requests containing base64-encoded payloads can help reduce risk until a full patch is applied. [1]


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