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nDPI/tests/cfgs/monitoring/result/stun_google_meet.pcapng.out
Adrian Pekar 5f312c0cd6
Fix JA4 fingerprinting (#2915) 
* Fix JA4 ALPN fingerprint to use first and last characters

According to the JA4 specification (line 2139), the ALPN field should
contain the first and last characters of the first ALPN extension value.

Currently, nDPI uses the first and second characters (alpn[0] and alpn[1]),
which produces incorrect fingerprints that don't match other JA4
implementations like Wireshark.

For example, with ALPN 'http/1.1':
- Current (incorrect): 'ht' (first + second char)
- Fixed (correct):     'h1' (first + last char)

This change ensures nDPI's JA4 implementation conforms to the official
specification and maintains interoperability with other JA4 tools.

Fixes: Incorrect JA4 ALPN fingerprint generation

* Fix JA4 ALPN implementation to correctly parse first ALPN protocol

The previous fix attempted to use strlen(ja->client.alpn)-1 but this was
insufficient because nDPI modifies the ALPN string by:
1. Adding null terminators that truncate the last character
2. Converting semicolons to dashes, affecting multi-protocol ALPNs

This complete fix:
- Adds alpn_original_last field to store the true last character
- Captures the last character of the FIRST ALPN protocol only (before ;/,)
- Preserves the original character before nDPI's string modifications

Now correctly implements JA4 spec: first + last characters of first ALPN protocol
Examples:
- ALPN 'h2;http/1.1' -> 'h2' (not 'h.' or 'h1')
- ALPN 'http/1.1' -> 'h1' (not 'ht' or 'h.')

Fixes: #2914

* Fix JA4 SNI detection to properly handle missing SNI extensions

Previously, nDPI incorrectly set JA4 SNI flag to 'd' (domain present) for
flows without any SNI extension. This was because the logic only checked
for NDPI_NUMERIC_IP_HOST risk (set when SNI contains IP) but didn't
distinguish between missing SNI and domain SNI.

Now properly detects:
- No SNI extension → 'i' flag
- SNI with IP address → 'i' flag
- SNI with domain → 'd' flag

This matches the JA4 specification.
2025-07-10 14:03:27 +02:00

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DPI Packets (UDP): 362 (51.71 pkts/flow)
Confidence DPI (cache) : 2 (flows)
Confidence DPI : 5 (flows)
Num dissector calls: 32 (4.57 diss/flow)
LRU cache ookla: 0/0/0 (insert/search/found)
LRU cache bittorrent: 0/0/0 (insert/search/found)
LRU cache stun: 20/10/2 (insert/search/found)
LRU cache tls_cert: 0/2/0 (insert/search/found)
LRU cache mining: 0/0/0 (insert/search/found)
LRU cache msteams: 0/0/0 (insert/search/found)
LRU cache fpc_dns: 0/0/0 (insert/search/found)
Automa host: 0/0 (search/found)
Automa domain: 0/0 (search/found)
Automa tls cert: 0/0 (search/found)
Automa risk mask: 0/0 (search/found)
Automa common alpns: 0/0 (search/found)
Patricia risk mask: 0/0 (search/found)
Patricia risk mask IPv6: 0/0 (search/found)
Patricia risk: 0/0 (search/found)
Patricia risk IPv6: 1/0 (search/found)
Patricia protocols: 6/6 (search/found)
Patricia protocols IPv6: 1/1 (search/found)
GoogleCall 362 74597 7
Acceptable 362 74597 7
VoIP 362 74597 7
JA Host Stats:
IP Address # JA4C
1 2001:b07:a3d:c112:48a1:1094:1227:281e 1
2 192.168.12.156 1
1 UDP [2001:b07:a3d:c112:48a1:1094:1227:281e]:45572 <-> [2001:4860:4864:6::81]:19305 [proto: 30.404/DTLS.GoogleCall][IP: 126/Google][Stream Content: Audio][Encrypted][Confidence: DPI][FPC: 78.404/STUN.GoogleCall, Confidence: DPI][DPI packets: 148][DPI packets before monitoring: 43][cat: VoIP/10][30 pkts/4693 bytes <-> 118 pkts/36197 bytes][Goodput ratio: 60/80][0.71 sec][bytes ratio: -0.770 (Download)][IAT c2s/s2c min/avg/max/stddev: 0/0 22/2 152/74 32/9][Pkt Len c2s/s2c min/avg/max/stddev: 106/99 156/307 608/1265 88/113][Mapped IP/Port: [2001:b07:a3d:c112:48a1:1094:1227:281e]:45572][RTP packets: 11/104][DTLSv1.2][JA4: dd2i110700_c45550529adf_d9dd6182da81][JA3S: 1f5d6a6d0bc5d514dd84d13e6283d309][Issuer: CN=hangouts][Subject: CN=hangouts][Certificate SHA-1: 07:CC:FC:28:04:F2:29:8F:E9:C4:BF:AC:F6:D2:BD:F2:BA:36:AD:31][Validity: 2023-10-11 02:02:47 - 2024-10-11 02:02:47][Cipher: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256][PLAIN TEXT (igoKAAiKAiADEA)][Plen Bins: 0,6,16,5,2,0,0,0,68,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
2 UDP 192.168.12.156:38152 <-> 142.250.82.76:19305 [proto: 30.404/DTLS.GoogleCall][IP: 126/Google][Stream Content: Audio][Encrypted][Confidence: DPI][FPC: 78.404/STUN.GoogleCall, Confidence: DPI][DPI packets: 74][DPI packets before monitoring: 43][cat: VoIP/10][28 pkts/4034 bytes <-> 46 pkts/12188 bytes][Goodput ratio: 71/84][0.87 sec][bytes ratio: -0.503 (Download)][IAT c2s/s2c min/avg/max/stddev: 0/0 30/10 205/154 50/29][Pkt Len c2s/s2c min/avg/max/stddev: 87/79 144/265 587/1245 89/180][Mapped IP/Port: 93.35.171.209:39032][RTP packets: 11/31][DTLSv1.2][JA4: dd2i110700_c45550529adf_d9dd6182da81][JA3S: 1f5d6a6d0bc5d514dd84d13e6283d309][Issuer: CN=hangouts][Subject: CN=hangouts][Certificate SHA-1: 49:1A:C7:70:3E:79:F9:C5:3D:0F:46:33:B7:A4:EC:54:B0:93:C9:61][Validity: 2023-06-19 17:32:20 - 2024-06-19 17:32:20][Cipher: TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256][PLAIN TEXT (HrRgpad)][Plen Bins: 0,8,37,9,4,0,0,0,38,0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0]
3 UDP 192.168.12.156:38152 <-> 142.250.82.76:3478 [proto: 30.404/DTLS.GoogleCall][IP: 126/Google][Stream Content: Audio][Encrypted][Confidence: DPI][FPC: 78.404/STUN.GoogleCall, Confidence: DPI][DPI packets: 79][DPI packets before monitoring: 43][cat: VoIP/10][55 pkts/7402 bytes <-> 24 pkts/3525 bytes][Goodput ratio: 69/71][6.63 sec][bytes ratio: 0.355 (Upload)][IAT c2s/s2c min/avg/max/stddev: 0/2 109/184 402/761 143/224][Pkt Len c2s/s2c min/avg/max/stddev: 87/82 135/147 423/579 69/115][Mapped IP/Port: 93.35.171.209:39032][RTP packets: 34/0][PLAIN TEXT (HrRgpad)][Plen Bins: 0,39,34,15,0,1,0,0,5,1,1,1,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
4 UDP 192.168.12.156:45400 <-> 142.250.82.76:3478 [proto: 78.404/STUN.GoogleCall][IP: 126/Google][ClearText][Confidence: DPI][FPC: 78.404/STUN.GoogleCall, Confidence: DPI][DPI packets: 33][DPI packets before monitoring: 33][cat: VoIP/10][17 pkts/2694 bytes <-> 16 pkts/1696 bytes][Goodput ratio: 73/60][54.70 sec][bytes ratio: 0.227 (Upload)][IAT c2s/s2c min/avg/max/stddev: 90/78 3250/2028 17905/6554 4698/2127][Pkt Len c2s/s2c min/avg/max/stddev: 158/106 158/106 166/106 2/0][Mapped IP/Port: 93.35.171.209:39033][RTP packets: 0/0][PLAIN TEXT (HrRgpad)][Plen Bins: 0,0,48,51,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
5 UDP 192.168.12.156:38152 <-> 74.125.128.127:19302 [proto: 78.404/STUN.GoogleCall][IP: 126/Google][ClearText][Confidence: DPI (cache)][FPC: 78/STUN, Confidence: DPI][DPI packets: 12][cat: VoIP/10][6 pkts/372 bytes <-> 6 pkts/444 bytes][Goodput ratio: 32/43][50.12 sec][bytes ratio: -0.088 (Mixed)][IAT c2s/s2c min/avg/max/stddev: 10019/10019 10022/10021 10026/10025 3/3][Pkt Len c2s/s2c min/avg/max/stddev: 62/74 62/74 62/74 0/0][Mapped IP/Port: 93.35.171.209:39032][PLAIN TEXT (kAGNNzv)][Plen Bins: 50,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
6 UDP 192.168.12.156:45400 <-> 74.125.128.127:19302 [proto: 78.404/STUN.GoogleCall][IP: 126/Google][ClearText][Confidence: DPI (cache)][FPC: 78/STUN, Confidence: DPI][DPI packets: 12][cat: VoIP/10][6 pkts/372 bytes <-> 6 pkts/444 bytes][Goodput ratio: 32/43][50.12 sec][bytes ratio: -0.088 (Mixed)][IAT c2s/s2c min/avg/max/stddev: 10020/10019 10022/10021 10026/10025 3/3][Pkt Len c2s/s2c min/avg/max/stddev: 62/74 62/74 62/74 0/0][Mapped IP/Port: 93.35.171.209:39033][PLAIN TEXT (tcEcaq476)][Plen Bins: 50,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
7 UDP 192.168.12.156:45400 <-> 142.250.82.76:19305 [proto: 78.404/STUN.GoogleCall][IP: 126/Google][ClearText][Confidence: DPI][FPC: 78.404/STUN.GoogleCall, Confidence: DPI][DPI packets: 4][cat: VoIP/10][2 pkts/324 bytes <-> 2 pkts/212 bytes][Goodput ratio: 74/60][0.63 sec][Mapped IP/Port: 93.35.171.209:39033][PLAIN TEXT (ByyD/CC)][Plen Bins: 0,0,50,50,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
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