ATT&CK coverage › Technique

Event Triggered Execution: Screensaver T1546.002

Adversaries may establish persistence by executing malicious content triggered by user inactivity. Screensavers are programs that execute after a configurable time of user inactivity and consist of Portable Executable (PE) files with a .scr file extension. The Windows screensaver application scrnsave.scr is located in <code>C:\Windows\System32\</code>, and <code>C:\Windows\sysWOW64\</code> on 64-bit Windows systems, along with screensavers included with base Windows installations.

Events covered

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

ProviderEvent IDTitle
Sysmon1Process creation
Sysmon11FileCreate
Sysmon12RegistryEvent (Object create and delete)
Sysmon13RegistryEvent (Value Set)
Sysmon14RegistryEvent (Key and Value Rename)
Security-Auditing4688A new process has been created.

Authoring guide

Patterns shared across the 5 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 (5 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
Image3ends_with 3\rundll32.exe, \explorer.exe, \reg.exe, \Bin\ccSvcHst.exe, \TiWorker.exe
TargetFilename2ends_with 1, match 1.scr, \uwfservicingscr.scr, \\\\127.0.0, \ADMIN$\
TargetObject1ends_with 1\Control Panel\Desktop\SCRNSAVE.EXE
CommandLine1match 1/d , HKCU\Control Panel\Desktop, .scr
registry_path1eq 1"*\\Control Panel\\Desktop\\SCRNSAVE.EXE*"

Top indicator values (24 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
TargetObjectends_with\Control Panel\Desktop\SCRNSAVE.EXE1
Imageends_with\explorer.exe112
Imageends_with\rundll32.exe176
CommandLinematch/d 12
Imageends_with\reg.exe146
CommandLinematch/t REG_SZ12
CommandLinematch/d 112
CommandLinematchHKEY_CURRENT_USER\Control Panel\Desktop1
CommandLinematch/v ScreenSaveTimeout1
CommandLinematch/v ScreenSaverIsSecure1
CommandLinematch.scr15
CommandLinematch/v SCRNSAVE.EXE1
CommandLinematch/v ScreenSaveActive1
CommandLinematch/f12
CommandLinematch/d 012
CommandLinematchHKCU\Control Panel\Desktop1
Imageends_with\TiWorker.exe17
Imageends_with\Kindle.exe1
TargetFilenameends_with\uwfservicingscr.scr1
Imageends_with\Bin\ccSvcHst.exe1

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 4 rules

Splunk 1 rule