Vulnerability Note VU#255484

OpenSSL contains integer overflow handling ASN.1 tags (1)

OpenSSL contains an integer overflow vulnerability in the way ASN.1 tags are handled. A specially crafted ASN.1 tag could cause the OpenSSL library to perform an out-of-bounds memory read operation. This could result in a denial of service, crashing the process using the OpenSSL library.

From the OpenSSL advisory:

2. Unusual ASN.1 tag values can cause an out of bounds read under
certain circumstances, resulting in a denial of service vulnerability.

All versions of SSLeay and versions of OpenSSL prior to 0.9.7c or 0.9.6k are vulnerable, as are operating systems and applications that use vulnerable SSLeay or OpenSSL libraries. The OpenSSL advisory describes as vulnerable "Any application that makes use of OpenSSL's ASN1 library to parse untrusted data. This includes all SSL or TLS applications, those using S/MIME (PKCS#7) or certificate generation routines."

The U.K. National Infrastructure Security Co-ordination Centre (NISCC) is tracking this vulnerability (VU#255484) and VU#380864 as NISCC/006489/openssl/1.

II. Impact

Upgrade to OpenSSL 0.9.7c or 0.9.6k. Alternatively, upgrade or apply a patch as specified by your vendor. Further information is available in an advisory from OpenSSL. Note that it is necessary to recompile any applications that are statically linked to OpenSSL libraries.

Systems Affected

http://www.uniras.gov.uk/vuls/2003/006489/openssl.htm
http://www.openssl.org/news/secadv_20030930.txt
http://wp.netscape.com/eng/ssl3/
http://www.ietf.org/rfc/rfc2246.txt
http://www.ietf.org/html.charters/pkix-charter.html
http://www.itu.int/ITU-T/studygroups/com10/languages/

Credit

This vulnerability was discovered and researched by NISCC.

This document was written by Art Manion.

Other Information

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