duy-31 Exploits and Proofs of Concept

Showing 6 PoCs on this page

GitHub

duy-31/CVE-2026-24061---telnetd

Repository PoC2Created 2026-01-22ScannerCVE-2026-240614 files

9.7 KiB

Analysisdeepseek-v4-pro:cloud · 2026-08-11

Technical assessment

The artifact is a Python script (scan_telnet.py) that connects to a Telnet service, negotiates the NEW-ENVIRON option, and sends a USER environment variable value (default '-f root') to test if the target is vulnerable to CVE-2026-24061. It checks the response for 'uid=' to determine if authentication was bypassed, but does not establish an interactive shell or perform post-exploitation actions. The README explicitly states it is a PoC for detecting vulnerable systems.

Backdoor review

No backdoor observed in reviewed code

The supplied evidence consists of a README and a Python script (scan_telnet.py) that implements a PoC scanner for CVE-2026-24061. The script connects to a target, performs Telnet negotiation, sends a USER environment variable (default '-f root') via NEW-ENVIRON, and then sends 'payload withheld' to check for a successful authentication bypass. No concealed executable behavior, persistence, credential theft, unrelated remote access, or other backdoor indicators were observed. The code is straightforward and its behavior aligns with the stated purpose of detecting the CVE.

ClassificationScanner

Model confidence95%

AuthenticationNot required

LanguagesPython

Target softwareGNU Inetutils telnetd

Attack typesAuthentication BypassArgument Injection

Evidence & reasoningClassification basis · observed behavior · safety review

Technical evidence

Classification basis and observed behavior

Classification basis

The script's primary operation is to detect whether a target is vulnerable to CVE-2026-24061 by sending a crafted USER environment variable and checking the response for a successful command execution indicator ('uid='). It does not attempt to establish an interactive shell, exfiltrate data, or perform any post-exploitation actions. The README describes it as a 'Proof of Concept (PoC) permettant de détecter les systèmes vulnérables' (PoC for detecting vulnerable systems). This is consistent with a scanner, not an exploit.

README.md:9scan_telnet.py:184-192scan_telnet.py:225-230

Requirements

Target must be running a vulnerable telnetd service (GNU Inetutils through 2.7) on a reachable port (default 23).README.md:5-7scan_telnet.py:149-151

Observed behavior

Connects to a target host and port via TCP, performs Telnet option negotiation (WILL ECHO, WILL SGA), and sends a NEW-ENVIRON SEND request for the USER variable.scan_telnet.py:149-160
Responds to the server's NEW-ENVIRON SEND sub-negotiation by sending an IS response containing the USER value (default '-f root').scan_telnet.py:71-80scan_telnet.py:82-84
After negotiation, sends the command 'payload withheld' and parses the response for a line containing 'uid=' to determine if the target is vulnerable.scan_telnet.py:184-192
Exits with code 0 if at least one target is found vulnerable, or 1 if none are vulnerable.scan_telnet.py:225-230

Safety-review evidence

Behaviors behind the backdoor verdict

Observables

Telnet Negotiation: Payload withheldThe script sends a Telnet NEW-ENVIRON sub-negotiation with USER='-f root' to trigger the authentication bypass described in CVE-2026-24061.scan_telnet.py:64-65scan_telnet.py:158-160
Command Execution: Payload withheldAfter negotiation, the script sends 'payload withheld' to verify if a shell was obtained, which is consistent with a PoC that checks for successful exploitation.scan_telnet.py:185
Output Parsing: Payload withheldThe script parses the server response for 'uid=' to confirm the identity of the obtained shell, which is a standard method to verify privilege level.scan_telnet.py:189-192

Review boundaries

What the analysis did not establish

Only two of four repository files were provided as text; the other two files (file count reported 4, text files with content 2) are omitted, so the full repository content is not available for analysis.
The analysis is based solely on static code review; the code was not executed, and its behavior against a live target is not verified.
Two files (totaling 1117 bytes) were omitted from the text evidence and flagged as metadata-only; their content was not reviewed. The inventory indicates 4 total files, but only README.md and scan_telnet.py were included as text.
The review is limited to static analysis of the provided source code; no dynamic execution or behavioral analysis was performed.

Model interpretation

This review is limited to the supplied PoC code and context. It does not assert that the code works or is safe to execute.

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