Creation Of Non-Existent System DLL

Severity: medium
Author: Nasreddine Bencherchali (Nextron Systems), fornotes
Source: upstream

Detects creation of specific system DLL files that are usually not present on the system (or at least not in system directories) but may be loaded by legitimate processes. Phantom DLL hijacking involves placing malicious DLLs with names of non-existent system binaries in locations where legitimate applications may search for them, leading to execution of the malicious DLLs. Thus, the creation of such DLLs may indicate preparation for phantom DLL hijacking attacks.

MITRE ATT&CK coverage

Tactic	Techniques
Persistence	`T1574.001` Hijack Execution Flow: DLL
Privilege Escalation	`T1574.001` Hijack Execution Flow: DLL
Defense Evasion	`T1574.001` Hijack Execution Flow: DLL

Event coverage

Provider	Event ID	Title
Sysmon	11	FileCreate

Stages and Predicates

Stage 1: `selection`

or:
TargetFilename|endswith: ':\Windows\System32\TSMSISrv.dll'
TargetFilename|endswith: ':\Windows\System32\TSVIPSrv.dll'
TargetFilename|endswith: ':\Windows\System32\WLBSCTRL.dll'
TargetFilename|endswith: ':\Windows\System32\WptsExtensions.dll'
TargetFilename|endswith: ':\Windows\System32\axeonoffhelper.dll'
TargetFilename|endswith: ':\Windows\System32\cdpsgshims.dll'
TargetFilename|endswith: ':\Windows\System32\oci.dll'
TargetFilename|endswith: ':\Windows\System32\offdmpsvc.dll'
TargetFilename|endswith: ':\Windows\System32\shellchromeapi.dll'
TargetFilename|endswith: ':\Windows\System32\wbem\wbemcomn.dll'
TargetFilename|endswith: ':\Windows\System32\wow64log.dll'
TargetFilename|endswith: '\SprintCSP.dll'

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.