Exfiltration Over Alternative Protocol: Exfiltration Over Symmetric Encrypted Non-C2 Protocol T1048.001

Tactic: Exfiltration

Adversaries may steal data by exfiltrating it over a symmetrically encrypted network protocol other than that of the existing command and control channel. The data may also be sent to an alternate network location from the main command and control server.

Events covered

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

Authoring guide

Patterns shared across the 2 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 (6 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
CommandLine1contains 1, match 1.*[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}.*, @, ftp:
EventType1in 1ProcessRollup2, exec, exec_event
Image1contains 1, ends_with 1\dnscat2, \iodine.exe
event.type1eq 1start
process.args1in 1, starts_with 1--data, --form, --upload-file
process_name1eq 1curl, curl.exe

Top indicator values (23 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
CommandLinecontains
@
13
CommandLinecontains
ftp:
12
CommandLinecontains
ftps:
12
CommandLinecontains
http:
15
CommandLinecontains
https:
15
CommandLinematch
.*[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}.*
12
EventTypein
ProcessRollup2
1117
EventTypein
exec
1171
EventTypein
exec_event
1139
EventTypein
executed
188
EventTypein
process_started
174
EventTypein
start
1134
Imagecontains
\dnscat2
1
Imageends_with
\iodine.exe
1
event.typeeq
start
1606
process.argsin
--form
12
process.argsin
--upload-file
1
process.argsin
-F
13
process.argsin
-T
1
process.argsin
-d
13
process.argsstarts_with
--data
1
process_nameeq
curl
118
process_nameeq
curl.exe
115

Exclusions (16 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
process.argswildcard
*ApiKey*
1
process.argswildcard
*Authorization*
1
process.argswildcard
*session.id*
1
process.argswildcard
-u
1
process.argswildcard
http*.aws.found.io*
1
process.argswildcard
http*.cisco.com/api/*
1
process.argswildcard
http*.elastic-cloud.com*
1
process.argswildcard
http*.elastic.cloud*
1
process.argswildcard
http*.elastic.dev*
1
process.argswildcard
http*.gcp.cloud.es.io*
1
process.argswildcard
http*.us-central1.run.app/*
1
process.argswildcard
http*127.0.0.*
1
process.argswildcard
http*localhost:*
1
process.argswildcard
http://192.168*
1
process.argswildcard
https://*/ap/fleet/*
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)

Sigma 1 rule

Elastic 1 rule