CVE-2017-7269
📋 TL;DR
This is a critical buffer overflow vulnerability in IIS 6.0 WebDAV service that allows remote attackers to execute arbitrary code on affected servers. Attackers can exploit it by sending specially crafted PROPFIND requests with long headers. Only Windows Server 2003 R2 systems running IIS 6.0 are affected.
💻 Affected Systems
- Microsoft Internet Information Services (IIS)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with remote code execution leading to full administrative control, data theft, ransomware deployment, or use as a foothold for lateral movement.
Likely Case
Remote code execution leading to web server compromise, website defacement, malware installation, or credential harvesting.
If Mitigated
Attack blocked at network perimeter or by WebDAV service disablement, resulting in no impact.
🎯 Exploit Status
Multiple public exploit tools available (ExplodingCan, IIS_exploit). Actively exploited in the wild since at least 2016.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: N/A
Restart Required: No
Instructions:
Microsoft ended support for Windows Server 2003 in 2015. No official patch exists. Migrate to supported Windows Server versions immediately.
🔧 Temporary Workarounds
Disable WebDAV service
windowsDisable the WebDAV extension in IIS 6.0 to prevent exploitation
1. Open IIS Manager
2. Right-click WebDAV extension
3. Select 'Disable'
Block PROPFIND requests
linuxConfigure firewall or web application firewall to block PROPFIND requests
iptables -A INPUT -p tcp --dport 80 -m string --string "PROPFIND" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "PROPFIND" --algo bm -j DROP
🧯 If You Can't Patch
- Isolate affected servers in separate network segments with strict firewall rules
- Implement web application firewall (WAF) with rules to detect and block exploit attempts
🔍 How to Verify
Check if Vulnerable:
Check if running Windows Server 2003 R2 with IIS 6.0 and WebDAV enabled. Use: systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Check Version:
systeminfo | findstr /B /C:"OS Name" /C:"OS Version"Verify Fix Applied:
Verify WebDAV is disabled in IIS Manager or test with exploit tools to confirm server is not vulnerable📡 Detection & Monitoring
Log Indicators:
- PROPFIND requests with long headers containing 'If: <http://'
- IIS 6.0 access logs showing 400/500 errors for WebDAV requests
Network Indicators:
- PROPFIND requests to port 80/443 with unusually long headers
- Traffic patterns matching known exploit tools
SIEM Query:
source="IIS" method="PROPFIND" header="If:*http://*" header_length>1000🔗 References
- http://www.securityfocus.com/bid/97127
- http://www.securitytracker.com/id/1038168
- https://0patch.blogspot.com/2017/03/0patching-immortal-cve-2017-7269.html
- https://github.com/danigargu/explodingcan
- https://github.com/edwardz246003/IIS_exploit
- https://github.com/rapid7/metasploit-framework/pull/8162
- https://medium.com/%40iraklis/number-of-internet-facing-vulnerable-iis-6-0-to-cve-2017-7269-8bd153ef5812
- https://support.microsoft.com/en-us/help/3197835/description-of-the-security-update-for-windows-xp-and-windows-server
- https://www.exploit-db.com/exploits/41738/
- https://www.exploit-db.com/exploits/41992/
- http://www.securityfocus.com/bid/97127
- http://www.securitytracker.com/id/1038168
- https://0patch.blogspot.com/2017/03/0patching-immortal-cve-2017-7269.html
- https://github.com/danigargu/explodingcan
- https://github.com/edwardz246003/IIS_exploit
- https://github.com/rapid7/metasploit-framework/pull/8162
- https://medium.com/%40iraklis/number-of-internet-facing-vulnerable-iis-6-0-to-cve-2017-7269-8bd153ef5812
- https://support.microsoft.com/en-us/help/3197835/description-of-the-security-update-for-windows-xp-and-windows-server
- https://www.exploit-db.com/exploits/41738/
- https://www.exploit-db.com/exploits/41992/
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2017-7269
