cbcvebase.
CVE-2009-1535
published 2009-06-10

CVE-2009-1535: The WebDAV extension in Microsoft Internet Information Services (IIS) 5.1 and 6.0 allows remote attackers to bypass URI-based protection mechanisms, and list…

PriorityP272high7.5CVSS 2.0
AVNACLAuNCPIPAP
EXPLOIT
EPSS
98.11%
99.9th percentile
The WebDAV extension in Microsoft Internet Information Services (IIS) 5.1 and 6.0 allows remote attackers to bypass URI-based protection mechanisms, and list folders or read, create, or modify files, via a %c0%af (Unicode / character) at an arbitrary position in the URI, as demonstrated by inserting %c0%af into a "/protected/" initial pathname component to bypass the password protection on the protected\ folder, aka "IIS 5.1 and 6.0 WebDAV Authentication Bypass Vulnerability," a different vulnerability than CVE-2009-1122.

Affected

3 ranges
VendorProductVersion rangeFixed in
microsoftinternet_information_services
microsoftinternet_information_services
microsoftinternet_information_services

Detection & IOCsextracted from sources · hover to see the quote

commandGET / %c0%af/protected/protected.zip HTTP/1.1 Translate: f Connection: close Host: servername
commandGET /prot%c0%afected/protected.zip HTTP/1.1 Translate: f Connection: close Host: servername
commandPROPFIND /protec%c0%afted/ HTTP/1.1
otherTranslate: f
uaneo/0.12.2
bytes
%c0%af
  • Detect HTTP requests containing the overlong UTF-8 encoded slash '%c0%af' anywhere in the URI path, combined with the 'Translate: f' header, targeting IIS 6.0 WebDAV endpoints — this is the canonical exploit pattern for CVE-2009-1535.
  • Flag PROPFIND requests containing '%c0%af' in the URI path; attackers use PROPFIND with this bypass to enumerate directory listings of password-protected WebDAV folders without authentication.
  • Flag PUT requests containing '%c0%af' in the URI path; the exploit allows unauthenticated file upload into protected WebDAV folders via this method.
  • The 'Translate: f' HTTP header is a required component of the bypass; its presence alongside '%c0%af' in the URI is a high-fidelity combined indicator for this attack.
  • The vulnerability is only exploitable when WebDAV is enabled on IIS 5.1 or 6.0 and the targeted folder requires Basic, Digest, or NTLM authentication; scope detection to those server versions and configurations.
  • ·ASP script source code cannot be downloaded via this bypass unless the server is explicitly configured to serve script source code.
  • ·The bypass only works against folders protected by authentication (Basic, Digest, or NTLM); unauthenticated/public folders are not relevant targets for this specific vulnerability.
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