zeek October 2018

zeek@lists.zeek.org

37 participants
26 discussions

by Ambros Novak

Holla! notice.log is extremely large before it rotates, sometimes 140G+. At times it rotates to another log with a timestamp added to it's name. This happened after turning on other analyzers. Is there a way to suppress notice.log or minimize the events written to it. The events in the other logs are more important. There are also other logs that are extremely large as well, and I'm trying to balance processing and space vs the visibility. Any advice appreciated. Merci!

2 years, 9 months

[Bro] Bro decapsulating ERSPAN (GRE)

by Matt Thoreson

Hello, I've got a vmware instance of Ubuntu running Bro 2.6-beta2. I want bro to monitor the eth0 interface that is directly receiving ERSPAN (gre tunneled) data from a Cisco switch. I've tried a few different scenarios. I thought Bro could by default recognize and decapsulate the real traffic from the GRE tunnel (according to the bro notes it should be able to do this) but so far when bro runs it just sees the gre traffic in it's weird.log. I've also tried creating another tunnel interface tun0 set up as GRE on the Ubuntu instance and have the traffic forwarded from eth0 to tun0 and have linux decapsulate it. That is not working either. Has anyone gotten something similar to work reading cisco ERSPAN traffic into bro?

2 years, 9 months

[Bro] Bro/Zeek project leadership update - welcome, Keith Lehigh!

by Vern Paxson

Adam Slagell decided earlier this year that it was time to step down from his service as the chair of the Bro/Zeek project's Leadership Team[*]. (He'll be continuing as a member of the LT.) The LT has enthusiastically selected Keith Lehigh of Indiana University to serve as its new chair. Many of you will know Keith from his service as this year's program committee chair of BroCon 2018. Our thanks to Adam for his industrious and invaluable service! Vern [*] https://www.bro.org/team.html

2 years, 9 months

[Bro] git submodule URL change

by Jon Siwek

FYI if you have an existing Bro git repo clone and want to update/pull the master branch and all submodules recursively, it will require syncing one time: git submodule sync --recursive That will update the URL for a git submodule that just changed. Afterwards, the usual update command will work: git submodule update --recursive --init New git clones Just Work. - Jon

2 years, 9 months

[Bro] bro, telnet.log

by qingyu chang

Hi, i'm writing a bro script to generate telnet.log, as showing in attachment. But when i simulate several remote telnet login actions, bro could't record all the login actions completely, lost nearly half. And if i run this script with PCAPs, it tuns out to be normal. Thanks for read my letter.

2 years, 9 months

[Bro] Syntax Question - Nested Switch Case

by TQ

Hello Bro Members, I apologize if this is not the right mailing list... I do not wish to spam everyone. I just picked up Bro a few days ago, to still learning the ropes. I have a syntax question that I can't seem to find anywhere. How do you do a nested switch case inside a record? I have some data 0xAABBCCDD01020304 or 0xAABBCCDD01020405 that I need to verify that the header is 0xAABBCCDD and switch based on the last two bytes, either 0x0304 or 0x0405. Is this a good practice of switch record since data length will change based on the command. The nested case I have below is incorrect and is throwing error "make[3]: *** [test_pac.h] Segmentation fault (core dumped)" Currently, I have: enum cmd_codes { NOP = 0x00000000, DEVICE_HEADER = 0x AABBCCDD, DEVICE_CMD2_1 = 0x0304, DEVICE_CMD2_2 = 0x0405 }; type Header = record { header: uint32; # header cmd1: uint16; # 0x0102 cmd2: uint16; # 0x0304 or 0x0405 } &byteorder=bigendian; type Device_Response = record { header: Device_Header; data: case(header.header) of { DEVICE_HEADER -> head: case(header.cmd2) of { DEVICE_CMD2_1 -> info1: Record_A; DEVICE_CMD2_2 -> info2: Record_B; }; # All the rest default -> unknown: bytestring &restofdata; }; } &byteorder=littleendian; type Record_A = record { # some data goes here } type Record_B = record { # some data goes here } Thanks!

2 years, 9 months

[Bro] Fwd: bro-postgresql Configuration example

by Evasion alert

2 years, 9 months

[Bro] Custom event handler script generates heavy CPU load with Bro 2.5.5 (PF_RING)

by Elena Bykovchenko

Hello. I have a script which defines a custom handler on mime_data event: event mime_all_data (c: connection, length: count, data: string) { // do stuff } When this script is ran with capturing traffic in PF_RING mode using lb_procs=2, Bro processes consume 100% of both pinned CPU cores. This is not the case when capturing without PF_RING in single process mode though. What are possible reasons for this? Can it be optimized on the script side? What can be done to lower the CPU usage?

2 years, 9 months

[Bro] Bro load with no traffic

by fatema bannatwala

Does anyone know why Bro would be using resources when no traffic flowing to the sensor? Recently we were having some ECC errors on one of our sensors and turned off the traffic to that sensor for troubleshooting purposes. Noticed that the load was pretty high (~7) on that sensor, and was wondering what Bro must be doing that would cause that load, shouldn't it be just waiting for the packets without using much cpu/memory resources on the box? Stats when no traffic flowing to the sensor, bro processes running because of cron on manager kicking the bro processes on the workers: $ top top - 12:18:17 up 13 days, 19:12, 2 users, * load average: 6.72, 7.05, 7.34* Tasks: 555 total, 9 running, 546 sleeping, 0 stopped, 0 zombie %Cpu(s): 9.7 us, 5.7 sy, 0.0 ni, 84.5 id, 0.0 wa, 0.0 hi, 0.1 si, 0.0 st KiB Mem : 13191564+total, 95957600 free, 32708392 used, 3249652 buff/cache KiB Swap: 8388600 total, 8388600 free, 0 used. 98285016 avail Mem When the traffic was turned back on, load average: $ top top - 10:39:52 up 1 day, 19:02, 2 users, load average: 12.89, 12.89, 12.82 Tasks: 551 total, 11 running, 540 sleeping, 0 stopped, 0 zombie %Cpu(s): 20.9 us, 6.1 sy, 0.1 ni, 72.4 id, 0.0 wa, 0.0 hi, 0.5 si, 0.0 st KiB Mem : 11540057+total, 59135456 free, 52346920 used, 3918204 buff/cache KiB Swap: 8388600 total, 8388600 free, 0 used. 62253548 avail Mem Any thoughts? :) Thanks, Fatema

2 years, 9 months

[Bro] - time diff between bro logs and host clock

by william de ping

Hi all, Any idea why new bro logs epoch timestamp is about 1 hour earlier than the actual clock of the host ? I am running a cluster and I was wondering how to fix this issue. Thank you, B

2 years, 9 months

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zeek October 2018