92480 2003-03-04 00:33 /101 rader/ Dave Ahmad <da@securityfocus.com> Importerad: 2003-03-04 00:33 av Brevbäraren Extern mottagare: bugtraq@securityfocus.com Mottagare: Bugtraq (import) <3791> Ärende: [Snort-2003-001] Buffer overflow in Snort RPC preprocessor (fwd) ------------------------------------------------------------ David Mirza Ahmad Symantec "sabbe dhamma anatta" 0x26005712 8D 9A B1 33 82 3D B3 D0 40 EB AB F0 1E 67 C6 1A 26 00 57 12 ---------- Forwarded message ---------- -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Snort Vulnerability Advisory [SNORT-2003-001] Date: 2003-03-03 Affected Snort Versions: Any version starting with version 1.8 to those before 2003-03-03 1PM/ US/Eastern including 1.9.0 and CVS HEAD (Snort 2.0beta) Synopsis: A buffer overflow has been found in the snort RPC normalization routines by ISS X-Force. This can cause snort to execute arbitrary code embedded within sniffed network packets. This preprocessor is enabled by default. Snort 1.9.1 has been released to resolve this issue. For users using CVS HEAD, a fix has been committed to the source tree. Mitigation: If you are in an environment that can not upgrade snort immediately, comment out the line in your snort.conf that begins: preprocessor rpc_decode and replace it with # preprocessor rpc_decode Details: When the rpc decoder normalizes fragmented RPC records, it incorrectly checks the lengths of what is being normalized against the current packet size. The rpc decoder in Snort 1.9.1 and above contains new alert options that can be used to help detect this attack Option Default State alert_fragments INACTIVE alert_large_fragments ACTIVE alert_incomplete ACTIVE alert_multiple_requests ACTIVE The first option will alert on any rpc fragmented record it finds. Large fragments will alert when the reassembled fragment record will exceed the current packet length. The incomplete record will alert when there is a partial record found. The alert_multiple_requests will alert when we find more than one RPC request per packet ( or reassembled packet ). Download Locations: Sourcefire has acquired additional bandwidth and hosting to aid users wishing to upgrade their Snort implementation. Binaries are currently not available, this is a source release only at this time. As new binaries become available they will be added to the site. Source code: http://www.snort.org/dl/snort-1.9.1.tar.gz GPG Signatures: http://www.snort.org/dl/snort-1.9.1.tar.gz.asc CVS HEAD (Snort 2.0beta) has been fixed as well. - -- Martin Roesch - Founder/CTO, Sourcefire Inc. - (410)290-1616 Sourcefire: Snort-based Enterprise Intrusion Detection Infrastructure roesch@sourcefire.com - http://www.sourcefire.com Snort: Open Source Network IDS - http://www.snort.org -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.7 (Darwin) iD8DBQE+Y+Rtqj0FAQQ3KOARAurPAJ9qzBQCzOG2xxcn2IBfuOlDMjPhJwCfdgiX M+f1Ccdy03evjCtBT1rq6YQ= =RhwD -----END PGP SIGNATURE----- (92480) /Dave Ahmad <da@securityfocus.com>/(Ombruten)