[Bro-Dev] [JIRA] (BIT-1427) rare SSH successful login heuristic FPs
Vern Paxson (JIRA)
jira at bro-tracker.atlassian.net
Sun Jun 21 09:19:00 PDT 2015
[ https://bro-tracker.atlassian.net/browse/BIT-1427?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=21006#comment-21006 ]
Vern Paxson commented on BIT-1427:
----------------------------------
Thanks, Vlad. I'll close this. Once we upgrade to 2.4, surely the Internet will provide another opportunity to test this :-P.
> rare SSH successful login heuristic FPs
> ---------------------------------------
>
> Key: BIT-1427
> URL: https://bro-tracker.atlassian.net/browse/BIT-1427
> Project: Bro Issue Tracker
> Issue Type: Problem
> Components: Bro
> Affects Versions: 2.3
> Reporter: Vern Paxson
>
> During a bruteforce attack that made 27M attempted logins, 2 were flagged as successful by one instance of Bro monitoring the traffic, but not by another running an identical config on the same traffic stream. I wasn't able to reproduce the FPs from bulk traces of the event. Both instances were associated with two Weirds, "SYN_after_close" and "excessive_data_without_further_acks" that were otherwise quite rare in the traffic. This suggests that there's a flaw in the heuristic whereby it's analyzing traffic streams that have confused state. Perhaps an adequate fix is to track whether a given flow has experienced those Weirds, and if so, don't apply the heuristic to it.
--
This message was sent by Atlassian JIRA
(v6.5-OD-05-041#65001)
More information about the bro-dev
mailing list