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Rule:
--
Sid:
111-14
--
Summary:
This event is generated when the pre-processor stream4
detects network traffic that may constitute an attack.
--
Impact:
Unknown. This may indicate an attempt to evade an IDS.
--
Detailed Information:
This event indicates that the pre-processor stream4 has detected forward
overlapping packets that may indicate an attempt is being made to evade
detection by an IDS.
--
Affected Systems:
All systems
--
Attack Scenarios:
An attacker can attempt to hide malicious payload data by sending
fragmented packets that overlap.
--
Ease of Attack:
Simple. Tools such as fragroute contain this functionality.
--
False Positives:
None Known.
--
False Negatives:
None Known.
--
Corrective Action:
Check the target host for signs of compromise.
Ensure the system is up to date with any appropriate vendor supplied patches.
--
Contributors:
Martin Roesch <roesch@sourcefire.com>
Sourcefire Vulnerability Research Team
Nigel Houghton <nigel.houghton@sourcefire.com>
--
Additional References:
--
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