7.5 High
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:P/I:P/A:P
0.345 Low
EPSS
Percentile
97.0%
A buffer overflow in the HTR ISAP extension on IIS servers could permit an intruder to interrupt the normal operation of IIS or possibly execute arbitrary code with the privileges of the HTR extension.
HTR is a server-side scripting technology for IIS which has largely been supplanted by ASP. `
`
There is a buffer overflow in the HTR ISAPI extension. By submitting a malicious HTR request, and intruder can exploit this buffer overflow.
An intruder can interrupt the normal operation of the IIS server. In addition, an intruder may be able to use this vulnerability to execute arbitrary code with the privileges of the HTR ISAPI extension. On IIS 4.0, this permits administrative control of the oeprating system; on IIS 5.0 and 5.1, this permits access with the privileges of the IWAM_computername account.
Apply a patch as decribed in MS02-018.
In addition to applying the patch (or if the patch cannot be applied) we strongly recommend disabling the HTR ISAPI extension. It has been the source of a number of vulnerabilities, including
<http://www.kb.cert.org/vuls/id/28565>
<http://www.kb.cert.org/vuls/id/264272>
<http://www.kb.cert.org/vuls/id/35085>
For some time, Microsoft has recommended disabling HTR unless there is a business-critical need to support it. Quoting from Microsoft Security Bulletin MS02-018:
_HTR is a first-generation advanced scripting technology delivered as part of IIS 2.0. HTR was never widely adopted, largely because a far superior technology, Active Server Pages (.ASP), was introduced in IIS 4.0 and became popular before customers had invested significant development resources in HTR. However, all versions of IIS through version 5.1 do provide support for HTR, for purposes of backward compatibility.
Microsoft has long advocated that customers disable HTR on their web servers, unless there is a business-critical need for the technology. By default, the IIS Lockdown Tool disable HTR support, by unmapping the HTR ISAPI extension._
As with any technology, we recommend disabling it if its not required.
363715
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Updated: September 13, 2002
Affected
We have not received a statement from the vendor.
The vendor has not provided us with any further information regarding this vulnerability.
Microsoft has released Microsoft Security Bulletin MS02-18.
If you have feedback, comments, or additional information about this vulnerability, please send us [email](<mailto:[email protected]?Subject=VU%23363715 Feedback>).
Group | Score | Vector |
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Base | ||
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Environmental |
Our thanks to Microsoft Corporation upon whose advisory this document is based. Microsoft has publicly thanked Dave Aitel of @Stake and Peter Grundl of KPMG for reporting this vulnerability.
This document was written by Shawn V. Hernan.
CVE IDs: | CVE-2002-0071 |
---|---|
Severity Metric: | 9.00 Date Public: |