Event Triggered Execution: AppInit DLLs T1546.010

Tactics: Privilege Escalation, Persistence

Adversaries may establish persistence and/or elevate privileges by executing malicious content triggered by AppInit DLLs loaded into processes. Dynamic-link libraries (DLLs) that are specified in the AppInit_DLLs value in the Registry keys HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows or HKEY_LOCAL_MACHINE\Software\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows are loaded by user32.dll into every process that loads user32.dll. In practice this is nearly every program, since user32.dll is a very common library.

Events covered

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

Authoring guide

Patterns shared across the 3 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 (7 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
TargetObject2contains 1, ends_with 1\\windows nt\\currentversion\\windows\\appinit_dlls, \software\microsoft\windows..., \software\wow6432node\microsoft\windows...
Details1eq 1(Empty)
EventID1eq 113
EventLog1eq 1Microsoft-Windows-Sysmon/Operational
NewName1ends_with 1\SOFTWARE\Microsoft\Windows..., \SOFTWARE\Wow6432Node\Microsoft\Windows...
event.type1eq 1change
registry_value_name1eq 1AppInit_Dlls

Top indicator values (10 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
Detailseq
(Empty)
12
EventIDeq
13
122
EventLogeq
Microsoft-Windows-Sysmon/Operational
110
NewNameends_with
\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_Dlls
1
NewNameends_with
\SOFTWARE\Wow6432Node\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_Dlls
1
TargetObjectcontains
\\windows nt\\currentversion\\windows\\appinit_dlls
1
TargetObjectends_with
\software\microsoft\windows nt\currentversion\windows\appinit_dlls
1
TargetObjectends_with
\software\wow6432node\microsoft\windows nt\currentversion\windows\appinit_dlls
1
event.typeeq
change
177
registry_value_nameeq
AppInit_Dlls
1

Exclusions (17 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
Detailseq
(Empty)
1
Imagewildcard
?:\program files (x86)\commvault\base\cvd.exe
1
Imagewildcard
?:\program files (x86)\commvault\contentstore*\base\cvd.exe
1
Imagewildcard
?:\program files\commvault\base\cvd.exe
1
Imagewildcard
?:\program files\commvault\contentstore*\base\cvd.exe
1
Imagewildcard
?:\program files\nvidia corporation\display.nvcontainer\nvdisplay.container.exe
1
Imagewildcard
?:\windows\system32\driverstore\filerepository\*\display.nvcontainer\nvdispla...
1
Imagewildcard
?:\windows\system32\msiexec.exe
1
Imagewildcard
?:\windows\syswow64\msiexec.exe
1
Imagewildcard
\device\harddiskvolume*\program files (x86)\commvault\base\cvd.exe
1
Imagewildcard
\device\harddiskvolume*\program files (x86)\commvault\contentstore*\base\cvd.exe
1
Imagewildcard
\device\harddiskvolume*\program files\commvault\base\cvd.exe
1
Imagewildcard
\device\harddiskvolume*\program files\commvault\contentstore*\base\cvd.exe
1
Imagewildcard
\device\harddiskvolume*\program files\nvidia...
1
Imagewildcard
\device\harddiskvolume*\windows\system32\driverstore\filerepository\*\display...
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

Kusto 1 rule