Bug #5076
open
keyword content does not work over reassembled TCP
Added by Philippe Antoine about 2 years ago.
Updated 10 months ago.
Description
Using rule
alert ip any any -> any any (content:"HTTP/2.loc"; sid:11;)
on attached pcap
with stream.reassembly.toserver-chunk-size=25
does not trigger an alert
It does trigger the alert without the setting.
I fear we might have an evasion if I split the packets over the default value of 2560...
Related issues
2 (2 open — 0 closed)
This was found during investigation of #4858
- Copied to Bug #5110: keyword content does not work over reassembled TCP (6.0.x backport) added
- Copied to Bug #5111: keyword content does not work over reassembled TCP (5.0.x backport) added
From talk with Victor, this is a known limitation, where the chunk size is supposed to be a bit random to protect against evasion attempts.
The solution may be to use hyperscan as a streaming engine (instead of running it on different chunks/blocks)
- Label deleted (
Needs backport)
- Target version changed from 7.0.0-beta1 to 8.0.0-beta1
- Related to Task #4431: libsuricata: Example showing libsuricata as a replacement for libnids (network grep) added
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