[Bro] IOCs data for hashes.

Azoff, Justin S jazoff at illinois.edu
Mon Aug 29 11:13:49 PDT 2016

> On Aug 29, 2016, at 2:00 PM, fatema bannatwala <fatema.bannatwala at gmail.com> wrote:
> Hi Chris,
> Thank you for the suggestions.
> The detect-MHR.bro script is already enabled in the local.bro file, but I don't get any
> logging in notice.log file corresponding to Malware hash registry.
> I looked at the script and the notice_threshold is set to 10 (10% min detection rate) which is reasonable,
> but as I was analyzing a malware hash, detected by other IDS device and when checked on team cymru's lookup: https://hash.cymru.com had 26% as detection rate, realized that there were no logs in
> files.log and notice.log files corresponding to that hash. 
> Bro didn't log any hash for the file transfer that transpired. 
> 1472425280.047247       Fs9rse1xsQgD2TIADa   x.x.x.x      CJFssC2o2RqHx6PJY8      HTTP    0       MD5,PE,SHA1     application/x-dosexec   -       11.101799       F       F       2122412 20265152      18142740 0

Those last 3 numbers are

seen_bytes    = 2122412
total_bytes   = 20265152
missing_bytes = 18142740

Bro did not see 90% of the bytes of the file, it can't hash what it didn't see.

- Justin Azoff

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