Application Layer Protocol: File Transfer Protocols T1071.002

Tactic: Command & Control

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 8 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 (11 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
src_ip2cidr_match 1, in 110.0.0.0/8, 127.0.0.0/8, 100.64.0.0/10, 169.254.0.0/16
All_Traffic.action1in 1allow, allowed
All_Traffic.app1eq 1smb
All_Traffic.src1in 110.0.0.0/8, 100.64.0.0/10, 127.0.0.0/8
DestinationPort1eq 1139, 445
DstPortNumber1in 120, 21
EventCategory1eq 1firewall
Type1eq 1
event_type1in 1childproc, netconn, proc

Top indicator values (70 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
EventIDeq
1
2237
All_Traffic.actionin
allow
13
All_Traffic.actionin
allowed
13
All_Traffic.appeq
smb
12
All_Traffic.srcin
10.0.0.0/8
1
All_Traffic.srcin
100.64.0.0/10
1
All_Traffic.srcin
127.0.0.0/8
1
All_Traffic.srcin
169.254.0.0/16
1
All_Traffic.srcin
172.16.0.0/12
1
All_Traffic.srcin
192.0.0.0/24
1
All_Traffic.srcin
192.0.0.0/29
1
All_Traffic.srcin
192.0.0.10/32
1
All_Traffic.srcin
192.0.0.170/32
1
All_Traffic.srcin
192.0.0.171/32
1
All_Traffic.srcin
192.0.0.8/32
1
All_Traffic.srcin
192.0.0.9/32
1
All_Traffic.srcin
192.0.2.0/24
1
All_Traffic.srcin
192.168.0.0/16
1
All_Traffic.srcin
192.175.48.0/24
1
All_Traffic.srcin
192.31.196.0/24
1
All_Traffic.srcin
192.52.193.0/24
1
All_Traffic.srcin
192.88.99.0/24
1
All_Traffic.srcin
198.18.0.0/15
1
All_Traffic.srcin
198.51.100.0/24
1
All_Traffic.srcin
203.0.113.0/24
1
All_Traffic.srcin
224.0.0.0/4
1
All_Traffic.srcin
240.0.0.0/4
1
All_Traffic.srcin
::1
1

Exclusions (54 distinct)

Field/operator/value combinations excluded by rules under this technique (top-level not() clauses), sorted by how many rules exclude each. These are the false-positive paths the community has learned to filter out. A new rule that ignores the high-count entries here will likely fire on the same noisy paths. Click a value to expand the rules under this technique that exclude it.

FieldKindValueRules excluding
All_Traffic.destin
10.0.0.0/8
1
All_Traffic.destin
100.64.0.0/10
1
All_Traffic.destin
127.0.0.0/8
1
All_Traffic.destin
169.254.0.0/16
1
All_Traffic.destin
172.16.0.0/12
1
All_Traffic.destin
192.0.0.0/24
1
All_Traffic.destin
192.0.0.0/29
1
All_Traffic.destin
192.0.0.10/32
1
All_Traffic.destin
192.0.0.170/32
1
All_Traffic.destin
192.0.0.171/32
1
All_Traffic.destin
192.0.0.8/32
1
All_Traffic.destin
192.0.0.9/32
1
All_Traffic.destin
192.0.2.0/24
1
All_Traffic.destin
192.168.0.0/16
1
All_Traffic.destin
192.175.48.0/24
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.

Platform (all)
Domain (all)

Splunk 7 rules

Kusto 1 rule