Microsoft IIS 5.0 allows the viewing of files through malformed URL
| iis-read-files (5903) |  Medium Risk |
Description:
Microsoft Internet Information Server (IIS) could allow a remote attacker to obtain source code fragments of known files, due to improper handling of requests by ISAPI extensions. A remote attacker could append .htr ISAPI extensions to the known file type of a URL request, allowing the attacker to obtain code fragments of the files. An attacker could use this vulnerability to gain access to sensitive information.
More information regarding the "File Fragment Reading via. HTR" vulnerability is available in Microsoft Security Bulletins MS00-031 and MS00-044. See References.
Platforms Affected:
- Microsoft, IIS 4.0
- Microsoft, IIS 5.0
Remedy:
Apply the patch for this vulnerability, as listed in Microsoft Security Bulletin MS01-004, MS01-041, or MS02-001. See References.
For best security practices, if .HTR functionality is not required, disable the .HTR script mapping, as listed in Microsoft Security Bulletin MS01-004. See References.
For Windows NT 4.0:
Microsoft originally provided patches for this vulnerability in MS00-031, MS00-044, MS01-041, and MS02-001 but they were superseded by the patch released with MS02-018. See References.
For Windows 2000:
Apply the appropriate patch for your system, as listed in Microsoft Security Bulletin MS02-001. See References.
For IIS:
Microsoft originally provided a patch for this vulnerability in MS02-018, but it was superseded by the patch released with MS02-062, and then superseded by the patch released with MS03-018. See References.
Consequences:
Obtain Information
References:
- CIAC Information Bulletin K-041, Denial of Service and File Reading Vulnerabilities in Microsoft IIS at http://www.ciac.org/ciac/bulletins/k-041.shtml.
- Georgi Guninski Security Advisory #33, IIS 5.0 allows viewing files using %3F+.htr at http://www.guninski.com/iishtr.html.
- Microsoft Security Bulletin MS00-031, Patch Available for 'Undelimited .HTR Request' and 'File Fragment Reading via .HTR' Vulnerabilities at http://www.microsoft.com/technet/security/bulletin/ms00-031.mspx.
- Microsoft Security Bulletin MS00-044, Patch Available for 'Absent Directory Browser Argument' Vulnerability at http://www.microsoft.com/technet/security/bulletin/ms00-044.mspx.
- Microsoft Security Bulletin MS01-004, Patch Available for New Variant of 'File Fragment Reading via .HTR' Vulnerability at http://www.microsoft.com/technet/security/bulletin/ms01-004.mspx.
- Microsoft Security Bulletin MS01-004 FAQ, Microsoft Security Bulletin (MS01-004): Frequently Asked Questions at http://www.microsoft.com/technet/security/bulletin/fq01-004.mspx.
- Microsoft Security Bulletin MS01-041, Malformed RPC Request Can Cause Service Failure at http://www.microsoft.com/technet/security/bulletin/ms01-041.mspx.
- Microsoft Security Bulletin MS02-001, Trusting Domains Do Not Verify Domain Membership of SIDs in Authorization Data at http://www.microsoft.com/technet/security/bulletin/ms02-001.mspx.
- Microsoft Security Bulletin MS02-018, Cumulative Patch for Internet Information Services (Q319733) at http://www.microsoft.com/technet/security/bulletin/ms02-018.mspx.
- Microsoft Security Bulletin MS02-062, Cumulative Patch for Internet Information Service (Q327696) at http://www.microsoft.com/technet/security/Bulletin/MS02-062.mspx.
- Microsoft Security Bulletin MS03-018, Cumulative Patch for Internet Information Service (811114) at http://www.microsoft.com/technet/security/bulletin/ms03-018.mspx.
- BID-2313: Microsoft IIS File Fragment Disclosure Vulnerability
- CVE-2001-0004: IIS 5.0 and 4.0 allows remote attackers to read the source code for executable web server programs by appending %3F+.htr to the requested URL, which causes the files to be parsed by the .HTR ISAPI extension, aka a variant of the File Fragment Reading via .HTR vulnerability.
- US-CERT VU#264272: Microsoft Internet Information Server (IIS) discloses contents of files via crafted request containing %3F+.htr
Reported:
Jan 08, 2001
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