CVE-2017-7269

CVE-2017-7269 is a buffer overflow (CWE-119) in Internet Information Services (IIS) 6.0, the web server shipped with Microsoft Windows Server 2003 R2. A remote attacker triggers it by sending a WebDAV PROPFIND request whose overly long header begins with 'If: <http://', overflowing a buffer during header parsing. Successful exploitation allows remote code execution on the affected web server, giving the attacker control of the host at the web service's privilege level. Only organizations still running IIS 6.0 on Windows Server 2003 R2 are affected, typically legacy web servers, since that OS reached end of support in July 2015. The flaw is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) and carries a 99.8% EPSS score (100th percentile), indicating active in-the-wild exploitation; no public PoC is recorded in this data and, because the OS is out of support, no generally distributed patch exists.

What to do: Inventory internet-facing systems still running IIS 6.0 on Windows Server 2003 R2 and prioritize migration to a supported Windows/IIS version, since no general patch was released for this out-of-support product (custom-support customers may be able to obtain a hotfix from Microsoft). As interim mitigation, disable WebDAV if it is not needed, or block or limit PROPFIND requests and long 'If' headers via IIS request filtering, a reverse proxy, or a WAF. Per the KEV entry, apply updates per vendor instructions; ransomware association is currently unknown.