dirkx at apache
Nov 6, 2009, 5:21 PM
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CVE-2009-3555 - apache/mod_ssl vulnerability and mitigation (final draft)
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Subject: CVE-2009-3555 - apache/mod_ssl vulnerability and mitigation
Apache httpd is affected by CVE-2009-3555[1] (The SSL Injection or MiM attack[2]).
We strongly urge you to upgrade to OpenSSL 0.9.8l; and to be prepared to deploy 0.9.8m as it becomes available[3]. Note that these are for short term and mid-term mitigation only; the long term solution may well require a modification of the SSL and/or TLS protocols[4].
For those who are not able to upgrade OpenSSL swiftly and/or for those who need detailed logging - we recommend that you roll out this patch[5]:
http://www.apache.org/dist/httpd/patches/apply_to_2.2.14/xx.
sha1: 28cd58f3758f1add39417333825b9d854f4f5f43
for mod_ssl as soon as possible. This is a partial fix in lieu of the protocol issues being addressed and further changes to OpenSSL. Like the OpenSSL 0.9.8l stopgap measure this patch rejects in-session renegotation.
If you are unable to patch and unable to roll our a newer version of OpenSSL, and you rely on Client Side Authentication with Certificates
then we recommend that you 1) ensure that you limit your configuration to a single 'SSLClient require' on VirtualHost/Sever level and 2) remove all other (re)negotiation/require directives. However this does NOT fully protect you - it just curtails authentication in this specific setting.
A version with this patch, Apache 2.2.15, is currently being readied[6].
Note that as mod_ssl is not part of the 1.3 branch distribution. A further announcement will be sent out when these are available.
1: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2009-3555
2: http://www.links.org/?p=780, http://extendedsubset.com/?p=8
3: http://www.openssl.org/source/
openssl-announce mailing list on
http://www.openssl.org/support/community.html
4: http://www.ietf.org/mail-archive/web/tls/current/msg03963.html
5: svn diff -r833581:833594 https://svn.apache.org/repos/asf/httpd/httpd/trunk/modules/ssl (| openssl sha1)
6: http://httpd.apache.org/
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