ATT&CK coverage › Technique

Proxy: External Proxy T1090.002

Adversaries may use an external proxy to act as an intermediary for network communications to a command and control server to avoid direct connections to their infrastructure. Many tools exist that enable traffic redirection through proxies or port redirection, including HTRAN, ZXProxy, and ZXPortMap. Adversaries use these types of proxies to manage command and control communications, to provide resiliency in the face of connection loss, or to ride over existing trusted communications paths to avoid suspicion.

Events covered

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

ProviderEvent IDTitle
Sysmon3Network connection
Security-Auditing5156The Windows Filtering Platform has permitted a connection.

Authoring guide

Patterns shared across the 2 rules above: which fields they filter on, what specific values they look for, and what they exclude. Field names are normalized 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 (8 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
DestinationHostname1ends_with 1.portmap.io
Initiated1eq 1true
SourcePort1eq 13389
Image1ends_with 1\thor.exe, \thor64.exe
FilterOrigin1eq 1AppContainer Loopback
src_ip1starts_with 1, eq 1127., ::1
dest_ip1starts_with 1, eq 1127., ::1
DestinationPort1eq 13389

Top indicator values (11 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.

FieldKindValueRules (here)Corpus reach
Initiatedeqtrue140
DestinationHostnameends_with.portmap.io1
dest_ipeq::11
dest_ipstarts_with127.1
src_ipstarts_with127.1
SourcePorteq338913
DestinationPorteq338913
src_ipeq::115
Imageends_with\thor.exe17
FilterOrigineqAppContainer Loopback1
Imageends_with\thor64.exe16

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