Suspicious Startup Folder Persistence

Severity: high
Author: Nasreddine Bencherchali (Nextron Systems), Swachchhanda Shrawan Poudel (Nextron Systems)
Source: upstream

Detects the creation of potentially malicious script and executable files in Windows startup folders, which is a common persistence technique used by threat actors. These files (.ps1, .vbs, .js, .bat, etc.) are automatically executed when a user logs in, making the Startup folder an attractive target for attackers. This technique is frequently observed in malvertising campaigns and malware distribution where attackers attempt to maintain long-term access to compromised systems.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1204.002` User Execution: Malicious File
Persistence	`T1547.001` Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder
Privilege Escalation	`T1547.001` Boot or Logon Autostart Execution: Registry Run Keys / Startup Folder

Event coverage

Provider	Event ID	Title
Sysmon	11	FileCreate

Stages and Predicates

Stage 1: `selection`

or:
TargetFilename|endswith: .bat
TargetFilename|endswith: .cmd
TargetFilename|endswith: .dll
TargetFilename|endswith: .hta
TargetFilename|endswith: .jar
TargetFilename|endswith: .js
TargetFilename|endswith: .jse
TargetFilename|endswith: .msi
TargetFilename|endswith: .ps1
TargetFilename|endswith: .psd1
TargetFilename|endswith: .psm1
TargetFilename|endswith: .scr
TargetFilename|endswith: .url
TargetFilename|endswith: .vba
TargetFilename|endswith: .vbe
TargetFilename|endswith: .vbs
TargetFilename|endswith: .wsf
TargetFilename|contains: '\Windows\Start Menu\Programs\Startup\'

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.