OpenBSD OpenSSH up to 3.3p1 Challenge-Response integer coercion

CVSS Meta Temp Score
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CTI Interest Score
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9.0$0-$5k0.00

Summaryinfo

A vulnerability was found in OpenBSD OpenSSH. It has been classified as critical. This impacts an unknown function of the component Challenge-Response Handler. The manipulation leads to integer coercion. This vulnerability is documented as CVE-2002-0639. Additionally, an exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in OpenBSD OpenSSH (Connectivity Software) and classified as critical. This issue affects an unknown code block of the component Challenge-Response Handler. The manipulation with an unknown input leads to a integer coercion vulnerability. Using CWE to declare the problem leads to CWE-192. Integer coercion refers to a set of flaws pertaining to the type casting, extension, or truncation of primitive data types. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Integer overflow in sshd in OpenSSH 2.9.9 through 3.3 allows remote attackers to execute arbitrary code during challenge response authentication (ChallengeResponseAuthentication) when OpenSSH is using SKEY or BSD_AUTH authentication.

The weakness was released 06/26/2002 by Mark Dowd with ISS X-Force as confirmed advisory (CERT.org). The advisory is shared at kb.cert.org. The identification of this vulnerability is CVE-2002-0639. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are unknown but a public exploit is available.

The exploit is available at securityfocus.com. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 14971 (Debian DSA-134-4 : ssh - remote exploit), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 38113 (OpenSSH Challenge-Response Authentication Integer Overflow Vulnerability).

Upgrading eliminates this vulnerability. A possible mitigation has been published even before and not after the disclosure of the vulnerability. Attack attempts may be identified with Snort ID 1812. Furthermore it is possible to detect and prevent this kind of attack with TippingPoint and the filter 1646.

The vulnerability is also documented in the databases at X-Force (9169), Tenable (14971), SecurityFocus (BID 5093†), OSVDB (6245†) and Vulnerability Center (SBV-656†). Entry connected to this vulnerability is available at VDB-18402. Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.0

VulDB Base Score: 10.0
VulDB Temp Score: 9.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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

NVD Base Score: 🔍

Exploitinginfo

Class: Integer coercion
CWE: CWE-192 / CWE-189
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 14971
Nessus Name: Debian DSA-134-4 : ssh - remote exploit
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
Nessus Port: 🔍

OpenVAS ID: 53850
OpenVAS Name: Debian Security Advisory DSA 134-1 (ssh)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍
Snort ID: 1812
Snort Message: SERVER-OTHER gobbles SSH exploit attempt
Snort Class: 🔍

Suricata ID: 2101812
Suricata Class: 🔍
Suricata Message: 🔍

TippingPoint: 🔍

McAfee IPS: 🔍
McAfee IPS Version: 🔍

SourceFire IPS: 🔍
ISS Proventia IPS: 🔍

Timelineinfo

06/24/2002 🔍
06/24/2002 +0 days 🔍
06/26/2002 +2 days 🔍
07/03/2002 +7 days 🔍
07/03/2002 +0 days 🔍
01/15/2003 +196 days 🔍
02/18/2003 +34 days 🔍
09/29/2004 +588 days 🔍
07/11/2014 +3572 days 🔍
09/14/2025 +4083 days 🔍

Sourcesinfo

Vendor: openbsd.org

Advisory: kb.cert.org
Researcher: Mark Dowd
Organization: ISS X-Force
Status: Confirmed

CVE: CVE-2002-0639 (🔍)
GCVE (CVE): GCVE-0-2002-0639
GCVE (VulDB): GCVE-100-18401
CERT: 🔍
X-Force: 9169
SecurityFocus: 5093 - OpenSSH Challenge-Response Buffer Overflow Vulnerabilities
OSVDB: 6245 - OpenSSH SKEY/BSD_AUTH Challenge-Response Remote Overflow
Vulnerability Center: 656 - Buffer Overflow in OpenSSH Challenge-Response Authentication, Critical

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 07/11/2014 14:23
Updated: 09/14/2025 21:27
Changes: 07/11/2014 14:23 (86), 05/08/2019 06:50 (6), 10/24/2024 14:23 (17), 09/14/2025 21:27 (2)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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