Subvert Trust Controls: Code Signing T1553.002

Tactic: Defense Impairment

Adversaries may create, acquire, or steal code signing materials to sign their malware or tools. Code signing provides a level of authenticity on a binary from the developer and a guarantee that the binary has not been tampered with. The certificates used during an operation may be created, acquired, or stolen by the adversary. Unlike Invalid Code Signature, this activity will result in a valid signature.

Events covered

6 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 (13 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
EventType2eq 2cs_invalidated, load
ObjectName1ends_with 1.AAA, .ZZZ
Provider_Name1eq 1Microsoft-Windows-Audit-CVE
dll.Ext.relative_file_creation_time1le 13600
dll.code_signature.status1eq 1errorExpired, errorRevoked
dll.name1eq 1aadauthhelper.dll, aadcloudap.dll, aadjcsp.dll
esf.event_type1eq 162
event.type1eq 1start
message1eq 1[CVE-2020-0601]
process.code_signature.exists1is_not_null 1
process.code_signature.status1starts_with 1?
process_id1eq 14
process_name1eq 1agentactivationruntimestarter.exe, agentservice.exe, aggregatorhost.exe

Top indicator values (3262 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
EventTypeeq
cs_invalidated
1
EventTypeeq
load
19
ObjectNameends_with
.AAA
1
ObjectNameends_with
.ZZZ
1
Provider_Nameeq
Microsoft-Windows-Audit-CVE
12
dll.Ext.relative_file_creation_timele
3600
1
dll.code_signature.statuseq
errorExpired
1
dll.code_signature.statuseq
errorRevoked
1
dll.nameeq
aadauthhelper.dll
1
dll.nameeq
aadcloudap.dll
1
dll.nameeq
aadjcsp.dll
1
dll.nameeq
aadtb.dll
1
dll.nameeq
aadwamextension.dll
1
dll.nameeq
aarsvc.dll
1
dll.nameeq
abovelockapphost.dll
1
dll.nameeq
accessibilitycpl.dll
1
dll.nameeq
accountaccessor.dll
1
dll.nameeq
accountsrt.dll
1
dll.nameeq
acgenral.dll
1
dll.nameeq
aclayers.dll
1
dll.nameeq
acledit.dll
1
dll.nameeq
aclui.dll
1
dll.nameeq
acmigration.dll
1
dll.nameeq
acppage.dll
1
dll.nameeq
acproxy.dll
1
dll.nameeq
acspecfc.dll
1
dll.nameeq
actioncenter.dll
1
dll.nameeq
actioncentercpl.dll
1
dll.nameeq
actionqueue.dll
1
dll.nameeq
activationclient.dll
1

Exclusions (93 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
Imagewildcard
?:\$windows.~bt\newos\windows\system32\ie4ushowie.exe
1
Imagewildcard
?:\program files (x86)\axence\nvision agent 2\nss\certutil.exe
1
Imagewildcard
?:\program files\git\usr\bin\find.exe
1
Imagewildcard
?:\program files\git\usr\bin\hostname.exe
1
Imagewildcard
?:\users\*\appdata\local\temp\{*}\taskkill.exe
1
Imagewildcard
?:\windows\temp\{*}\taskkill.exe
1
ImageLoadedstarts_with
?:\$windows.~bt\newos\windows\system32\
1
ImageLoadedstarts_with
?:\$windows.~bt\newos\windows\winsxs\
1
ImageLoadedstarts_with
?:\$windows.~bt\sources\
1
ImageLoadedstarts_with
?:\$windows.~bt\work\
1
ImageLoadedstarts_with
?:\windows\assembly\nativeimages_v
1
ImageLoadedstarts_with
?:\windows\softwaredistribution\download\
1
ImageLoadedstarts_with
?:\windows\system32\
1
ImageLoadedstarts_with
?:\windows\systemtemp\
1
ImageLoadedstarts_with
?:\windows\syswow64\
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 2 rules

Elastic 4 rules