Non-Application Layer Protocol T1095

Adversaries may use an OSI non-application layer protocol for communication between host and C2 server or among infected hosts within a network. The list of possible protocols is extensive. Specific examples include use of network layer protocols, such as the Internet Control Message Protocol (ICMP), transport layer protocols, such as the User Datagram Protocol (UDP), session layer protocols, such as Socket Secure (SOCKS), as well as redirected/tunneled protocols, such as Serial over LAN (SOL).

Events covered

7 catalog events are tagged with this technique by at least one rule.

Authoring guide

Patterns shared across the 11 rules above: which fields they filter on, what specific values they look for, and what they exclude. The catalog normalizes field names across vendors so Sigma's Image, Elastic's process.name, and Splunk's process_name collapse into one row. Each rule contributes at most once per row.

Fields filtered most (12 distinct)

The fields most rules look at when detecting this technique. The How column shows the operators authors use (eq, wildcard, regex_match, match) and how often each appears. Sample values are concrete examples to start from, not an exhaustive list.

FieldRulesHowSample values
EventID8eq 81, 4104, 4688, 5156, 4625
CommandLine4regex_match 3, contains 1(?i)(\-\-dns)?((\s+)|(\=))?((server\=)|(host\=))?((\d{1,3..., --lua-exec , --sh-exec , -l --proxy-type http
Type2eq 2
Data1contains 1powercat , powercat.ps1
Image1ends_with 1\nc.exe, \ncat.exe, \netcat.exe
ParentCommandLine1match 1.*[0-9]{1,3}(\.[0-9]{1,3}){3}.*
_raw1regex_match 1(?i)(Process ID:(\s+)?4[^\d])|share|ntlm
event.type1eq 1start
process.parent.args1eq 1, wildcard 1-*l*, -*p*, -e
process.parent.args_count1eq 15
process_name1eq 1cmd.exe, powershell.exe
signature_id1eq 14625, 5140, 5156

Top indicator values (35 distinct)

Specific (field, operator, value) combinations the rules check for, ranked by how many rules under this technique use each one. The Corpus reach column counts how many rules across the entire catalog (any technique) check the same combination. High numbers point to widely-used indicators that are likely noisy on their own; combine them with another condition for useful signal. Blank means the combination is specific to rules under this technique. Click a value to expand the rules under this technique that use it.

FieldKindValueRules (here)Corpus reach
CommandLineregex_match
(?i)(\-\-dns)?((\s+)|(\=))?((server\=)|(host\=))?((\d{1,3}\.\d{1,3}\.\d{1,3}\...
33
EventIDeq
1
2232
EventIDeq
4104
2268
EventIDeq
4688
2312
EventIDeq
5156
215
EventIDeq
4625
115
EventIDeq
5140
18
CommandLinecontains
--lua-exec
1
CommandLinecontains
--sh-exec
1
CommandLinecontains
-l --proxy-type http
1
CommandLinecontains
-l -v -p
1
CommandLinecontains
-lv -p
1
CommandLinecontains
-lvnp
1
CommandLinecontains
-lvp
1
CommandLinecontains
-vnl --exec
1
CommandLinecontains
-vnl -e
1
Datacontains
powercat
1
Datacontains
powercat.ps1
1
Imageends_with
\nc.exe
1
Imageends_with
\ncat.exe
1
Imageends_with
\netcat.exe
1
ParentCommandLinematch
.*[0-9]{1,3}(\.[0-9]{1,3}){3}.*
1
_rawregex_match
(?i)(Process ID:(\s+)?4[^\d])|share|ntlm
1
event.typeeq
start
1241
process.parent.argseq
-e
1
process.parent.argseq
cmd.exe
1
process.parent.argseq
powershell.exe
1
process.parent.argswildcard
-*l*
1
process.parent.argswildcard
-*p*
1
process.parent.args_counteq
5
1

Rules under this technique

Every rule in the catalog tagged with this technique, grouped by vendor. Click a rule title for its full predicates, exclusions, and indicators.

Sigma 2 rules

Elastic 1 rule

Splunk 8 rules