Snort mailing list archives
RE: [Snort-2003-001] Buffer overflow in Snort RPC p reprocessor
From: "Slighter, Tim" <tslighter () itc nrcs usda gov>
Date: Mon, 3 Mar 2003 14:24:04 -0700
my real point is that the only way a snort system running on a stealth interface could potentially become a point of ingress is if the intruder is capable of passing intructive code to enable the interface with an IP address. Add to that, providing the snort system is running in stealth, how is the intruder ever going to know where the overflow has taken place in order to follow up and attempt to compromise that system? Perhaps if they went after the MAC, but our system is running in non-promiscuous and stealth and I just do not understand how an intruder is ever going to locate this system and let along compromise it. Add to that IPTABLES and additional filtering and that snort is running in daemon mode as a different user than superuser. Taking all of this into account, can someone please enlighten me on how an intruder is going to compromise the snort system? -----Original Message----- From: Michael Anderson [mailto:mca () arlut utexas edu] Sent: Monday, March 03, 2003 1:47 PM To: Slighter, Tim Cc: 'snort-users () lists sourceforge net' Subject: Re: [Snort-users] [Snort-2003-001] Buffer overflow in Snort RPC p reprocessor I think this is an incorrect assumption. Your snort's rpc preprocessor will read the traffic and be subject to malicious code regardless of whether your interface is stealth or not. You could probably use the vulnerability to crash snort thus making you blind to other attacks. -Mike Slighter, Tim wrote:
Should it - or could it be specified that users running snort on a stealth interface would not be impacted? -----Original Message----- From: Martin Roesch [mailto:roesch () sourcefire com] Sent: Monday, March 03, 2003 11:00 AM Subject: [Snort-users] [Snort-2003-001] Buffer overflow in Snort RPC preprocessor -----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+Y5gfqj0FAQQ3KOARAkENAJ0Zf0tGT/BilYA32bIuQF0Te/A2bgCfWRu2 OoXy1dQb8B/1/AEbTDqjxSA= =NQ8d -----END PGP SIGNATURE----- ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://www.geocrawler.com/redir-sf.php3?list=snort-users
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Current thread:
- RE: [Snort-2003-001] Buffer overflow in Snort RPC p reprocessor Slighter, Tim (Mar 03)
- <Possible follow-ups>
- RE: [Snort-2003-001] Buffer overflow in Snort RPC p reprocessor Slighter, Tim (Mar 03)
- Re: [Snort-2003-001] Buffer overflow in Snort RPC p reprocessor Michael Anderson (Mar 03)