Dr S N Henson of the OpenSSL core team and Open Network Security recently
developed an ASN1 test suite for NISCC (www.niscc.gov.uk). When the test suite
was run against OpenSSL a denial of service vulnerability was discovered.
Certain types of public key can take disproportionate amounts of time to
process. This could be used by an attacker in a denial of service attack.
Any code which uses OpenSSL to parse ASN1 data from untrusted sources is
affected. This includes SSL servers which enable client authentication and
This issue was co-ordinated through NISCC although currently no patch exists.
The final patch will reject keys which exceed certain limits. These limits are
similar to those already enforced by other crypto libraries such as NSS.
Embargo until 20060928
Also affects (all RHEL)
Created attachment 137035 [details]
proposed patch CVE-2006-2940
Created attachment 137036 [details]
replacement patch CVE-2006-2940
removing embargo, public at http://www.openssl.org/news/secadv_20060928.txt
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.