Application Layer Protocol: File Transfer Protocols T1071.002

Adversaries may communicate using application layer protocols associated with transferring files to avoid detection/network filtering by blending in with existing traffic. Commands to the remote system, and often the results of those commands, will be embedded within the protocol traffic between the client and server.

Events covered

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

Authoring guide

Patterns shared across the 6 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 (4 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
CommandLine6regex_match 6(?i)ftp\s+(.{1,})?\-s\:.{1,}\.\w{2,5}, (\s+\-[Nvw]+\s+\d+?.*?(((\d{1,3}\.){3}\d{1,3})|(\w?\wtps?..., (\s+\-[Nvw]+\s+\d+?.*?(((\d{1,3}\.){3}\d{1,3})|(\w?\wtps?...
EventID4eq 41, 4104, 4688
Type1eq 1
event_type1in 1childproc, netconn, proc

Top indicator values (9 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)ftp\s+(.{1,})?\-s\:.{1,}\.\w{2,5}
33
CommandLineregex_match
(\s+\-[Nvw]+\s+\d+?.*?(((\d{1,3}\.){3}\d{1,3})|(\w?\wtps?\:(\/\/|\x5c\x5c)))\...
22
CommandLineregex_match
(\s+\-[Nvw]+\s+\d+?.*?(((\d{1,3}\.){3}\d{1,3})|(\w?\wtps?\:(\/\/|\x5c\x5c)))\...
1
EventIDeq
1
2232
EventIDeq
4104
1268
EventIDeq
4688
1312
event_typein
childproc
127
event_typein
netconn
127
event_typein
proc
127

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.

Splunk 6 rules