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ssl: detect duplicate client handshake #10059

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ssl: detect duplicate client handshake #10059

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1 change: 1 addition & 0 deletions rules/tls-events.rules
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Original file line number Diff line number Diff line change
Expand Up @@ -34,5 +34,6 @@ alert tls any any -> any any (msg:"SURICATA TLS certificate invalid der"; flow:e
alert tls any any -> any any (msg:"SURICATA TLS certificate invalid subject"; flow:established; app-layer-event:tls.certificate_invalid_subject; flowint:tls.anomaly.count,+,1; classtype:protocol-command-decode; sid:2230028; rev:1;)
alert tls any any -> any any (msg:"SURICATA TLS certificate invalid issuer"; flow:established; app-layer-event:tls.certificate_invalid_issuer; flowint:tls.anomaly.count,+,1; classtype:protocol-command-decode; sid:2230029; rev:1;)
alert tls any any -> any any (msg:"SURICATA TLS certificate invalid validity"; flow:established; app-layer-event:tls.certificate_invalid_validity; flowint:tls.anomaly.count,+,1; classtype:protocol-command-decode; sid:2230030; rev:1;)
alert tls any any -> any any (msg:"SURICATA TLS duplicate handshake message"; flow:established; app-layer-event:tls.duplicate_handshake_message; flowint:tls.anomaly.count,+,1; classtype:protocol-command-decode; sid:2230031; rev:1;)

#next sid is 2230031
21 changes: 21 additions & 0 deletions src/app-layer-ssl.c
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Expand Up @@ -119,6 +119,7 @@ SCEnumCharMap tls_decoder_event_table[] = {
{ "CERTIFICATE_INVALID_ISSUER", TLS_DECODER_EVENT_CERTIFICATE_INVALID_ISSUER },
{ "CERTIFICATE_INVALID_VALIDITY", TLS_DECODER_EVENT_CERTIFICATE_INVALID_VALIDITY },
{ "ERROR_MESSAGE_ENCOUNTERED", TLS_DECODER_EVENT_ERROR_MSG_ENCOUNTERED },
{ "DUPLICATE_HANDSHAKE_MESSAGE", TLS_DECODER_EVENT_DUPLICATE_HANDSHAKE_MESSAGE },
/* used as a generic error event */
{ "INVALID_SSL_RECORD", TLS_DECODER_EVENT_INVALID_SSL_RECORD },
{ NULL, -1 },
Expand Down Expand Up @@ -1498,6 +1499,16 @@ static int SSLv3ParseHandshakeType(SSLState *ssl_state, const uint8_t *input,

switch (ssl_state->curr_connp->handshake_type) {
case SSLV3_HS_CLIENT_HELLO:
if (ssl_state->flags & SSL_AL_FLAG_STATE_CLIENT_HELLO) {
SSLSetEvent(ssl_state, TLS_DECODER_EVENT_DUPLICATE_HANDSHAKE_MESSAGE);
if (ssl_state->client_connp.ja3_str) {
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why is the ja3 stuff freed here?

Ja3BufferFree(&ssl_state->client_connp.ja3_str);
}
if (ssl_state->client_connp.ja3_hash) {
SCFree(ssl_state->client_connp.ja3_hash);
ssl_state->client_connp.ja3_hash = NULL;
}
}
ssl_state->current_flags = SSL_AL_FLAG_STATE_CLIENT_HELLO;

rc = TLSDecodeHandshakeHello(ssl_state, input, input_len);
Expand All @@ -1506,6 +1517,16 @@ static int SSLv3ParseHandshakeType(SSLState *ssl_state, const uint8_t *input,
break;

case SSLV3_HS_SERVER_HELLO:
if (ssl_state->flags & SSL_AL_FLAG_STATE_SERVER_HELLO) {
SSLSetEvent(ssl_state, TLS_DECODER_EVENT_DUPLICATE_HANDSHAKE_MESSAGE);
if (ssl_state->server_connp.ja3_str) {
Ja3BufferFree(&ssl_state->server_connp.ja3_str);
}
if (ssl_state->server_connp.ja3_hash) {
SCFree(ssl_state->server_connp.ja3_hash);
ssl_state->server_connp.ja3_hash = NULL;
}
}
ssl_state->current_flags = SSL_AL_FLAG_STATE_SERVER_HELLO;

DEBUG_VALIDATE_BUG_ON(ssl_state->curr_connp->message_length != input_len);
Expand Down
1 change: 1 addition & 0 deletions src/app-layer-ssl.h
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Expand Up @@ -70,6 +70,7 @@ enum {
TLS_DECODER_EVENT_CERTIFICATE_INVALID_ISSUER,
TLS_DECODER_EVENT_CERTIFICATE_INVALID_VALIDITY,
TLS_DECODER_EVENT_ERROR_MSG_ENCOUNTERED,
TLS_DECODER_EVENT_DUPLICATE_HANDSHAKE_MESSAGE,
TLS_DECODER_EVENT_INVALID_SSL_RECORD,
};

Expand Down