Debian DSA-394-1 : openssl095 - ASN.1 parsing vulnerability

critical Nessus Plugin ID 15231


The remote Debian host is missing a security-related update.


Steve Henson of the OpenSSL core team identified and prepared fixes for a number of vulnerabilities in the OpenSSL ASN1 code that were discovered after running a test suite by British National Infrastructure Security Coordination Centre (NISCC).

A bug in OpenSSLs SSL/TLS protocol was also identified which causes OpenSSL to parse a client certificate from an SSL/TLS client when it should reject it as a protocol error.

The Common Vulnerabilities and Exposures project identifies the following problems :

- CAN-2003-0543 :
Integer overflow in OpenSSL that allows remote attackers to cause a denial of service (crash) via an SSL client certificate with certain ASN.1 tag values.

- CAN-2003-0544 :

OpenSSL does not properly track the number of characters in certain ASN.1 inputs, which allows remote attackers to cause a denial of service (crash) via an SSL client certificate that causes OpenSSL to read past the end of a buffer when the long form is used.

- CAN-2003-0545 :

Double-free vulnerability allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via an SSL client certificate with a certain invalid ASN.1 encoding. This bug was only present in OpenSSL 0.9.7 and is listed here only for reference.


Upgrade the libssl095a packages and restart services using this library. Debian doesn't ship any packages that are linked against this library.

For the stable distribution (woody) this problem has been fixed in openssl095 version 0.9.5a-6.woody.3.

This package is not present in the unstable (sid) or testing (sarge) distribution.

The following commandline (courtesy of Ray Dassen) produces a list of names of running processes that have libssl095 mapped into their memory space :

find /proc -name maps -exec egrep -l 'libssl095' {} /dev/null \; | sed -e 's/[^0-9]//g' | xargs --no-run-if-empty ps --no-headers -p | sed -e 's/^\+//' -e 's/ \+/ /g' | cut -d ' ' -f 5 | sort | uniq

You should restart the associated services.

See Also

Plugin Details

Severity: Critical

ID: 15231

File Name: debian_DSA-394.nasl

Version: 1.29

Type: local

Agent: unix

Published: 9/29/2004

Updated: 1/4/2021

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information


Risk Factor: Medium

Score: 6.7


Risk Factor: Critical

Base Score: 10

Temporal Score: 7.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:openssl095, cpe:/o:debian:debian_linux:3.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/11/2003

Vulnerability Publication Date: 7/14/2003

Reference Information

CVE: CVE-2003-0543, CVE-2003-0544, CVE-2003-0545

BID: 8732

CWE: 119

DSA: 394