Bug #4232: Protocol detection evasion enip-SMB - Suricata - Open Information Security Foundation

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Bug #4232

closed

Protocol detection evasion enip-SMB

Added by Philippe Antoine almost 4 years ago. Updated about 3 years ago.

Status:

Closed

Priority:

Normal

Assignee:

Philippe Antoine

Target version:

7.0.0-beta1

Affected Versions:

6.0.1

Effort:

Difficulty:

Label:

Needs backport, Needs backport to 5.0, Needs backport to 6.0

Description

Found by oss-fuzz
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28388

Problem is that rs_smb_probe_tcp uses search_smb_record. which searches a SMB record at any position
Before this record, there might be another valid protocol such as ENIP

Why is not parse_nbss_record_partial good enough ?

Files

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input.pcap (340 Bytes) input.pcap	SMB detected	Philippe Antoine, 01/21/2021 11:13 AM
input2.pcap (330 Bytes) input2.pcap	ENIP detected on shorter payload	Philippe Antoine, 01/21/2021 11:13 AM

Related issues 2 (0 open — 2 closed)

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Updated by Victor Julien almost 4 years ago

Status changed from New to Feedback
Assignee changed from Victor Julien to Philippe Antoine

Philippe can you craft a pcap for this?

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Updated by Philippe Antoine almost 4 years ago

File input.pcap input.pcap added
File input2.pcap input2.pcap added

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Updated by Philippe Antoine almost 4 years ago

Reproduced with suricata -r input2.pcap -k none -c suricata.yaml -l log. with enip activated in suricata.yaml
Then jq '.app_proto' log/eve.json

To produce the pcaps, I used this script

#!/usr/bin/env python
from scapy.all import *
import binascii

pktsTCP3WHS = []

pktsTCP3WHS += Ether(dst='00:01:02:03:04:07', src='00:01:02:03:04:05')/ \
    IP(dst='1.2.3.4', src='5.6.7.8')/TCP(sport=44818, dport=445, flags='S',seq=1000)
pktsTCP3WHS += Ether(src='00:01:02:03:04:07', dst='00:01:02:03:04:05')/ \
    IP(src='1.2.3.4', dst='5.6.7.8')/TCP(dport=44818, sport=445, flags='S''A', seq=2000, ack=1001)
pktsTCP3WHS += Ether(dst='00:01:02:03:04:07', src='00:01:02:03:04:05')/ \
    IP(dst='1.2.3.4', src='5.6.7.8')/TCP(sport=44818, dport=445, flags='A',seq=1001, ack=2001)

payloadSMB = "FF534D42202020202020" 
payloadBase = "04002020202020206A0000002020202020202020202020202020" 
pktSMB = [Ether(dst='00:01:02:03:04:07', src='00:01:02:03:04:05')/ \
    IP(dst='1.2.3.4', src='5.6.7.8')/TCP(sport=44818, dport=445, flags='P''A',seq=1001, ack=2001)/binascii.unhexlify(payloadBase+payloadSMB)]
pktsSMB = pktsTCP3WHS + pktSMB

wrpcap('input.pcap', pktsSMB)

pktENIP = [Ether(dst='00:01:02:03:04:07', src='00:01:02:03:04:05')/ \
    IP(dst='1.2.3.4', src='5.6.7.8')/TCP(sport=44818, dport=445, flags='P''A',seq=1001, ack=2001)/binascii.unhexlify(payloadBase)]
pktsENIP = pktsTCP3WHS + pktENIP

wrpcap('input2.pcap', pktsENIP)