CVE-2003-0543

OpenSSL 0.9.6 and 0.9.7 - Denial of Service via ASN.1 Tag Integer Overflow

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2003-0543. PoCs published by Bram Matthys.

AI-analyzed exploit summary This exploit is a brute-forcer targeting OpenSSL ASN.1 parsing vulnerabilities (CVE-2003-0543). It sends corrupted client certificates to an SSL server, potentially causing crashes or resource exhaustion.

Description

Integer overflow in OpenSSL 0.9.6 and 0.9.7 allows remote attackers to cause a denial of service (crash) via an SSL client certificate with certain ASN.1 tag values.

Exploits (1)

exploitdb WORKING POC VERIFIED
by Bram Matthys · cdosmultiple
https://www.exploit-db.com/exploits/146

This exploit is a brute-forcer targeting OpenSSL ASN.1 parsing vulnerabilities (CVE-2003-0543). It sends corrupted client certificates to an SSL server, potentially causing crashes or resource exhaustion.

Classification
Working Poc 95%
Attack Type
Dos
Complexity
Moderate
Reliability
Reliable
Target: OpenSSL <=0.9.6j and <=0.9.7b
No auth needed
Prerequisites: Network access to target SSL server · Target server must be running vulnerable OpenSSL version
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (16)

Core 16
Core References
Various Sources x_refsource_confirm
http://www-1.ibm.com/support/docview.wss?uid=swg21247112
Third Party Advisory, VDB Entry vdb-entry signature x_refsource_oval
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5292
Vendor Advisory vendor-advisory x_refsource_redhat
http://www.redhat.com/support/errata/RHSA-2003-292.html
US Government Resource third-party-advisory x_refsource_cert-vn
http://www.kb.cert.org/vuls/id/255484
Third Party Advisory vdb-entry x_refsource_vupen
http://www.vupen.com/english/advisories/2006/3900
Third Party Advisory vendor-advisory x_refsource_debian
http://www.debian.org/security/2003/dsa-393
Third Party Advisory vendor-advisory x_refsource_debian
http://www.debian.org/security/2003/dsa-394
Patch, Vendor Advisory vendor-advisory x_refsource_redhat
http://www.redhat.com/support/errata/RHSA-2003-291.html
US Government Resource third-party-advisory x_refsource_cert
http://www.cert.org/advisories/CA-2003-26.html
Third Party Advisory third-party-advisory x_refsource_secunia
http://secunia.com/advisories/22249
Third Party Advisory, VDB Entry vdb-entry signature x_refsource_oval
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A4254
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/8732
Vendor Advisory vendor-advisory x_refsource_sunalert
http://sunsolve.sun.com/search/document.do?assetkey=1-66-201029-1
Various Sources vendor-advisory x_refsource_engarde
http://www.linuxsecurity.com/advisories/engarde_advisory-3693.html

Scores

EPSS 0.2465
EPSS Percentile 97.6%

Details

Status published
Products (2)
openssl/openssl 0.9.6
openssl/openssl 0.9.7
Published Nov 17, 2003
Tracked Since Feb 18, 2026