Microsoft IIS 4.0/5.0 HTR ISAPI Extension ism.dll Variable Name memory corruption

CVSS Meta Temp Score
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7.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Microsoft IIS 4.0/5.0. It has been rated as critical. Impacted is an unknown function in the library ism.dll of the component HTR ISAPI Extension. This manipulation as part of Variable Name causes memory corruption. This vulnerability is tracked as CVE-2002-0071. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in Microsoft IIS 4.0/5.0 (Web Server) and classified as critical. Affected by this vulnerability is an unknown function in the library ism.dll of the component HTR ISAPI Extension. The manipulation as part of a Variable Name leads to a memory corruption vulnerability. The CWE definition for the vulnerability is CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

Buffer overflow in the ism.dll ISAPI extension that implements HTR scripting in Internet Information Server (IIS) 4.0 and 5.0 allows attackers to cause a denial of service or execute arbitrary code via HTR requests with long variable names.

The bug was discovered 04/10/2002. The weakness was disclosed 04/10/2002 by Dave Aitel with @stake as confirmed advisory (CERT.org). It is possible to read the advisory at kb.cert.org. This vulnerability is known as CVE-2002-0071. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 10932 (Microsoft IIS .HTR ISAPI Filter Enabled), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Web Servers and running in the context r. The commercial vulnerability scanner Qualys is able to test this issue with plugin 10577 (Microsoft IIS Malformed HTR Request Buffer Overflow Vulnerability (MS02-018)).

Upgrading eliminates this vulnerability. Attack attempts may be identified with Snort ID 1618. Furthermore it is possible to detect and prevent this kind of attack with TippingPoint and the filter 8174.

The vulnerability is also documented in the databases at X-Force (8799), Tenable (10932), SecurityFocus (BID 4474†), OSVDB (3325†) and Vulnerability Center (SBV-304†). The entries VDB-18071, VDB-18070, VDB-18069 and VDB-18068 are pretty similar. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Memory corruption
CWE: CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 10932
Nessus Name: Microsoft IIS .HTR ISAPI Filter Enabled
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍
Snort ID: 1618
Snort Message: SERVER-IIS .asp chunked Transfer-Encoding
Snort Class: 🔍

Suricata ID: 2101809
Suricata Class: 🔍
Suricata Message: 🔍

TippingPoint: 🔍

McAfee IPS: 🔍
McAfee IPS Version: 🔍

SourceFire IPS: 🔍
ISS Proventia IPS: 🔍
PaloAlto IPS: 🔍

Timelineinfo

04/10/2002 🔍
04/10/2002 +0 days 🔍
04/10/2002 +0 days 🔍
04/10/2002 +0 days 🔍
04/22/2002 +12 days 🔍
04/22/2002 +0 days 🔍
12/08/2002 +230 days 🔍
01/06/2004 +394 days 🔍
07/11/2014 +3838 days 🔍
09/23/2025 +4092 days 🔍

Sourcesinfo

Vendor: microsoft.com

Advisory: kb.cert.org
Researcher: Dave Aitel
Organization: @stake
Status: Confirmed

CVE: CVE-2002-0071 (🔍)
GCVE (CVE): GCVE-0-2002-0071
GCVE (VulDB): GCVE-100-18067

OVAL: 🔍

CERT: 🔍
X-Force: 8799
SecurityFocus: 4474 - Microsoft IIS HTR ISAPI Extension Buffer Overflow Vulnerability
OSVDB: 3325 - Microsoft IIS HTR ISAPI Overflow
Vulnerability Center: 304 - [cisco-sa-20020415-ms02-018] IIS .HTR vulnerability, Medium

See also: 🔍

Entryinfo

Created: 07/11/2014 13:50
Updated: 09/23/2025 04:41
Changes: 07/11/2014 13:50 (88), 01/21/2025 07:07 (17), 09/23/2025 04:41 (2)
Complete: 🔍
Cache ID: 216::103

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