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modified GSSAPI analyzer to parse NTLM and KRB tokens

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This commit is contained in:
Justin Oursler 2017-10-11 13:42:54 -04:00
parent 45ee32db49
commit 57bfbc02b1
2 changed files with 56 additions and 27 deletions
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76
src/analyzer/protocol/gssapi/gssapi-analyzer.pac
View file

@ -28,31 +28,63 @@ refine connection GSSAPI_Conn += {
function forward_blob(val: GSSAPI_NEG_TOKEN_MECH_TOKEN, is_orig: bool): bool function forward_blob(val: GSSAPI_NEG_TOKEN_MECH_TOKEN, is_orig: bool): bool
%{ %{
if ( val->oid()->meta()->length() >= 7 && if ( ${val.token}.length() >= 7 &&
memcmp("NTLMSSP", val->oid()->content().begin(), 7) == 0 ) memcmp("NTLMSSP", ${val.token}.begin(), 7) == 0 )
{ {
// ntlmssp // ntlmssp
if ( ! ntlm ) if ( ! ntlm )
ntlm = analyzer_mgr->InstantiateAnalyzer("NTLM", bro_analyzer()->Conn()); ntlm = analyzer_mgr->InstantiateAnalyzer("NTLM", bro_analyzer()->Conn());
if ( ntlm ) if ( ntlm )
ntlm->DeliverStream(${val.mech_token}.length(), ${val.mech_token}.begin(), is_orig); ntlm->DeliverStream(${val.token}.length(),
} ${val.token}.begin(), is_orig);
else if ( val->oid()->meta()->length() == 9 && }
(memcmp("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02", val->oid()->content().begin(), val->oid()->meta()->length()) == 0 ||
memcmp("\x2a\x86\x48\x82\xf7\x12\x01\x02\x02", val->oid()->content().begin(), val->oid()->meta()->length()) == 0 ) )
{
// krb5 && ms-krb5
if ( ! krb5 )
krb5 = analyzer_mgr->InstantiateAnalyzer("KRB", bro_analyzer()->Conn());
// 0x0100 is a special marker
if ( krb5 && memcmp("\x01\x00", ${val.mech_token}.begin(), 2) == 0 )
{
krb5->DeliverPacket(${val.mech_token}.length()-2, ${val.mech_token}.begin()+2, is_orig, 0, 0, 0);
}
}
else if ( 0x60 == *(${val.token}.begin()) )
{
// probably KRB
const unsigned char *p = ${val.token}.begin();
int len_to_send = ${val.token}.length();
p++;
len_to_send--;
int shift = 1;
if ( ((*p) & 0x80) > 0 )
{
shift += (*p) & 0x7f;
}
p += shift; // eating an ASN.1 meta
len_to_send -= shift;
// should now be pointing at OID
if ( (*p) == 0x06 )
{
p++;
len_to_send--;
len_to_send -= (*p) + 1;
p += (*p) + 1; // eating the OID. assuming short form on
// OID len
// should now be pointing at the type of KRB
// 0x0100 or 0x0200
// krb5 && ms-krb5
if ( ! krb5 )
krb5 = analyzer_mgr->InstantiateAnalyzer("KRB", bro_analyzer()->Conn());
if ( krb5 && (
memcmp("\x01\x00", p, 2) == 0 || // KRB5 AP REQ
memcmp("\x02\x00", p, 2) == 0 ) // KRB5 AP REP
)
{
krb5->DeliverPacket(len_to_send-2,
p+2,
is_orig, 0, 0, 0);
}
}
}
return true; return true;
%} %}

7
src/analyzer/protocol/gssapi/gssapi-protocol.pac
View file

@ -50,9 +50,6 @@ type GSSAPI_NEG_TOKEN_RESP_Arg = record {
}; };
type GSSAPI_NEG_TOKEN_MECH_TOKEN(is_orig: bool) = record { type GSSAPI_NEG_TOKEN_MECH_TOKEN(is_orig: bool) = record {
meta : ASN1EncodingMeta; meta : ASN1EncodingMeta;
mech_token_meta : ASN1EncodingMeta; token : bytestring &length=meta.length;
oid : ASN1Encoding;
mech_token : bytestring &restofdata;
}; };