# Stream events -- rules for matching on TCP stream engine events.
#
# SID's fall in the 2210000+ range. See http://doc.emergingthreats.net/bin/view/Main/SidAllocation
#
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake with ack in wrong dir"; stream-event:3whs_ack_in_wrong_dir; classtype:protocol-command-decode; sid:2210000; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake async wrong sequence"; stream-event:3whs_async_wrong_seq; classtype:protocol-command-decode; sid:2210001; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake right seq wrong ack evasion"; stream-event:3whs_right_seq_wrong_ack_evasion; classtype:protocol-command-decode; sid:2210002; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake SYNACK in wrong direction"; stream-event:3whs_synack_in_wrong_direction; classtype:protocol-command-decode; sid:2210003; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake SYNACK resend with different ack"; stream-event:3whs_synack_resend_with_different_ack; classtype:protocol-command-decode; sid:2210004; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake SYNACK resend with different seq"; stream-event:3whs_synack_resend_with_diff_seq; classtype:protocol-command-decode; sid:2210005; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake SYNACK to server on SYN recv"; stream-event:3whs_synack_toserver_on_syn_recv; classtype:protocol-command-decode; sid:2210006; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake SYNACK with wrong ack"; stream-event:3whs_synack_with_wrong_ack; classtype:protocol-command-decode; sid:2210007; rev:2;)
# Excessive SYN/ACKs within a session. Limit is set in stream engine, "stream.max-synack-queued".
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake excessive different SYN/ACKs"; stream-event:3whs_synack_flood; classtype:protocol-command-decode; sid:2210055; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake SYN resend different seq on SYN recv"; stream-event:3whs_syn_resend_diff_seq_on_syn_recv; classtype:protocol-command-decode; sid:2210008; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake SYN to client on SYN recv"; stream-event:3whs_syn_toclient_on_syn_recv; classtype:protocol-command-decode; sid:2210009; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 3way handshake wrong seq wrong ack"; stream-event:3whs_wrong_seq_wrong_ack; classtype:protocol-command-decode; sid:2210010; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 4way handshake SYNACK with wrong ACK"; stream-event:4whs_synack_with_wrong_ack; classtype:protocol-command-decode; sid:2210011; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 4way handshake SYNACK with wrong SYN"; stream-event:4whs_synack_with_wrong_syn; classtype:protocol-command-decode; sid:2210012; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 4way handshake wrong seq"; stream-event:4whs_wrong_seq; classtype:protocol-command-decode; sid:2210013; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM 4way handshake invalid ack"; stream-event:4whs_invalid_ack; classtype:protocol-command-decode; sid:2210014; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM CLOSEWAIT ACK out of window"; stream-event:closewait_ack_out_of_window; classtype:protocol-command-decode; sid:2210015; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM CLOSEWAIT FIN out of window"; stream-event:closewait_fin_out_of_window; classtype:protocol-command-decode; sid:2210016; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM CLOSEWAIT invalid ACK"; stream-event:closewait_invalid_ack; classtype:protocol-command-decode; sid:2210017; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM CLOSING ACK wrong seq"; stream-event:closing_ack_wrong_seq; classtype:protocol-command-decode; sid:2210018; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM CLOSING invalid ACK"; stream-event:closing_invalid_ack; classtype:protocol-command-decode; sid:2210019; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED packet out of window"; stream-event:est_packet_out_of_window; classtype:protocol-command-decode; sid:2210020; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED SYNACK resend"; stream-event:est_synack_resend; classtype:protocol-command-decode; sid:2210022; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED SYNACK resend with different ACK"; stream-event:est_synack_resend_with_different_ack; classtype:protocol-command-decode; sid:2210023; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED SYNACK resend with different seq"; stream-event:est_synack_resend_with_diff_seq; classtype:protocol-command-decode; sid:2210024; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED SYNACK to server"; stream-event:est_synack_toserver; classtype:protocol-command-decode; sid:2210025; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED SYN resend"; stream-event:est_syn_resend; classtype:protocol-command-decode; sid:2210026; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED SYN resend with different seq"; stream-event:est_syn_resend_diff_seq; classtype:protocol-command-decode; sid:2210027; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED SYN to client"; stream-event:est_syn_toclient; classtype:protocol-command-decode; sid:2210028; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED invalid ack"; stream-event:est_invalid_ack; classtype:protocol-command-decode; sid:2210029; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN invalid ack"; stream-event:fin_invalid_ack; classtype:protocol-command-decode; sid:2210030; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN1 ack with wrong seq"; stream-event:fin1_ack_wrong_seq; classtype:protocol-command-decode; sid:2210031; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN1 FIN with wrong seq"; stream-event:fin1_fin_wrong_seq; classtype:protocol-command-decode; sid:2210032; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN1 invalid ack"; stream-event:fin1_invalid_ack; classtype:protocol-command-decode; sid:2210033; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN2 ack with wrong seq"; stream-event:fin2_ack_wrong_seq; classtype:protocol-command-decode; sid:2210034; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN2 FIN with wrong seq"; stream-event:fin2_fin_wrong_seq; classtype:protocol-command-decode; sid:2210035; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN2 invalid ack"; stream-event:fin2_invalid_ack; classtype:protocol-command-decode; sid:2210036; rev:2;)
# very common when looking at midstream traffic after IDS started
#alert tcp any any -> any any (msg:"SURICATA STREAM FIN recv but no session"; stream-event:fin_but_no_session; classtype:protocol-command-decode; sid:2210037; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM FIN out of window"; stream-event:fin_out_of_window; classtype:protocol-command-decode; sid:2210038; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM Last ACK with wrong seq"; stream-event:lastack_ack_wrong_seq; classtype:protocol-command-decode; sid:2210039; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM Last ACK invalid ACK"; stream-event:lastack_invalid_ack; classtype:protocol-command-decode; sid:2210040; rev:2;)
# very common when looking at midstream traffic after IDS started
#alert tcp any any -> any any (msg:"SURICATA STREAM RST recv but no session"; stream-event:rst_but_no_session; classtype:protocol-command-decode; sid:2210041; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM TIMEWAIT ACK with wrong seq"; stream-event:timewait_ack_wrong_seq; classtype:protocol-command-decode; sid:2210042; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM TIMEWAIT invalid ack"; stream-event:timewait_invalid_ack; classtype:protocol-command-decode; sid:2210043; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM Packet with invalid timestamp"; stream-event:pkt_invalid_timestamp; classtype:protocol-command-decode; sid:2210044; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM Packet with invalid ack"; stream-event:pkt_invalid_ack; classtype:protocol-command-decode; sid:2210045; rev:2;)
# Broken TCP: ack field non 0, but ACK flag not set. http://ask.wireshark.org/questions/3183/acknowledgment-number-broken-tcp-the-acknowledge-field-is-nonzero-while-the-ack-flag-is-not-set
# Often result of broken load balancers, firewalls and such.
#alert tcp any any -> any any (msg:"SURICATA STREAM Packet with broken ack"; stream-event:pkt_broken_ack; classtype:protocol-command-decode; sid:2210051; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM SHUTDOWN RST invalid ack"; stream-event:rst_invalid_ack; classtype:protocol-command-decode; sid:2210046; rev:2;)
# SYN (re)send during shutdown (closing, closewait, finwait1, finwait2, lastack, timewait states)
#alert tcp any any -> any any (msg:"SURICATA STREAM SYN resend"; stream-event:shutdown_syn_resend; classtype:protocol-command-decode; sid:2210049; rev:2;)
# Sequence gap: missing data in the reassembly engine. Usually due to packet loss. Will be very noisy on a overloaded link / sensor.
#alert tcp any any -> any any (msg:"SURICATA STREAM reassembly sequence GAP -- missing packet(s)"; stream-event:reassembly_seq_gap; classtype:protocol-command-decode; sid:2210048; rev:2;)
alert tcp any any -> any any (msg:"SURICATA STREAM reassembly overlap with different data"; stream-event:reassembly_overlap_different_data; classtype:protocol-command-decode; sid:2210050; rev:2;)
# Bad Window Update: see bug 1238 for an explanation
alert tcp any any -> any any (msg:"SURICATA STREAM bad window update"; stream-event:pkt_bad_window_update; classtype:protocol-command-decode; sid:2210056; rev:1;)

# retransmission detection
#
# The rules below match on retransmissions detected in various stages of the
# stream engine. They are all "noalert" rules that increment the counter
# tcp.retransmission.count. The last rule sid:2210054 matches if the counter
# reaches 10. Increase this number if the rule is too noisy.
#
# "regular" retransmissions, only count
alert tcp any any -> any any (msg:"SURICATA STREAM ESTABLISHED retransmission packet before last ack"; stream-event:est_pkt_before_last_ack; flowint:tcp.retransmission.count,+,1; noalert; classtype:protocol-command-decode; sid:2210021; rev:3;)
# retransmission, only count
alert tcp any any -> any any (msg:"SURICATA STREAM CLOSEWAIT retransmission packet before last ack"; stream-event:closewait_pkt_before_last_ack; flowint:tcp.retransmission.count,+,1; noalert; classtype:protocol-command-decode; sid:2210052; rev:3;)
# retransmission of pkt before reassembly window, only count
alert tcp any any -> any any (msg:"SURICATA STREAM reassembly segment before base seq (retransmission)"; stream-event:reassembly_segment_before_base_seq; flowint:tcp.retransmission.count,+,1; noalert; classtype:protocol-command-decode; sid:2210047; rev:2;)
# count "general" retransmissions
alert tcp any any -> any any (msg:"SURICATA STREAM Packet is retransmission"; stream-event:pkt_retransmission; flowint:tcp.retransmission.count,+,1; noalert; classtype:protocol-command-decode; sid:2210053; rev:1;)
# rule to alert if a stream has excessive retransmissions
alert tcp any any -> any any (msg:"SURICATA STREAM excessive retransmissions"; flowbits:isnotset,tcp.retransmission.alerted; flowint:tcp.retransmission.count,>=,10; flowbits:set,tcp.retransmission.alerted; classtype:protocol-command-decode; sid:2210054; rev:1;)

# next sid 2210057