Observing POP3 recognized as FTP - Suricata 7.0.9

hi Suricata Team,

I am testing suricata 7.0.9 and seeing that pop3 is recognized as FTP by suricata 7.0.9.

I found the below threads online, which is related to suricata 7.0.1, is this issue still relavant for suricata 7.0.9 ?

I have attached the packet captures of the pop3 flow from my testing.

threads regarding pop3 identified as FTP.

sample pop3 capture from my test

pop3.pcapng (445.1 KB)


Date: 6/9/2025 – 13:30:30 (uptime: 0d, 00h 08m 00s)

Counter | TM Name | Value

ips.accepted | Total | 40
ips.blocked | Total | 28
ips.drop_reason.flow_drop | Total | 24
ips.drop_reason.applayer_error | Total | 4
capture.kernel_packets | Total | 68
capture.afpacket.polls | Total | 47669
capture.afpacket.poll_timeout | Total | 47602
capture.afpacket.poll_data | Total | 67
decoder.pkts | Total | 68
decoder.bytes | Total | 4956
decoder.ipv4 | Total | 68
decoder.ethernet | Total | 68
decoder.tcp | Total | 68
tcp.syn | Total | 4
tcp.synack | Total | 4
tcp.rst | Total | 8
decoder.vlan | Total | 68
decoder.avg_pkt_size | Total | 72
decoder.max_pkt_size | Total | 127
tcp.active_sessions | Total | 4
flow.total | Total | 4
flow.active | Total | 4
flow.tcp | Total | 4
flow.wrk.spare_sync_avg | Total | 100
flow.wrk.spare_sync | Total | 3
tcp.sessions | Total | 4
tcp.ssn_from_pool | Total | 4
tcp.segment_from_cache | Total | 23
tcp.segment_from_pool | Total | 9
app_layer.flow.ftp | Total | 4
app_layer.tx.ftp | Total | 16
app_layer.error.ftp.parser | Total | 4
flow.mgr.full_hash_pass | Total | 86
flow.mgr.rows_per_sec | Total | 11796
flow.spare | Total | 9700
flow.mgr.rows_maxlen | Total | 1
flow.mgr.flows_checked | Total | 4
flow.mgr.flows_notimeout | Total | 4
memcap_pressure | Total | 18
memcap_pressure_max | Total | 18
tcp.memuse | Total | 6225920
tcp.reassembly_memuse | Total | 1146880
ftp.memuse | Total | 892
flow.memuse | Total | 7154304

thanks in advance
Cherish

Thanks for this report, did you test with master as well ? (I think pop3 support has evolved with a full parser in 8)

1 Like

thankyou philippe antoine, i havent tested any version beyond 7.0.9. hoping to test with master / suricata 8 and update this topic.

regards
cherish

It is fixed in Suricata 8, but not back ported to Suricata 7 which has no POP3 support

1 Like

Hello,

Sorry to dig this up, but it’s not fixed in version 8.0.2.

Our OpenVPN server listens on port 110 TCP and some bots send POP3 messages detected as protocol FTP.

I get the impression that the commit never reached master?