InfraGuard

Detection rule: Invalid ACK

Packets with an ACK number inconsistent with session state.

WarningTCP Stream IntegritySuricata

What it detects

Packets with an ACK number inconsistent with session state.

Why it fires

Possible blind injection or abnormal ACKs from scanning tools.

Worst case

Blind injection

Matching signatures

invalid ackinvalid ack

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