Sigma rule: Suspicious Shell Open Command Registry Modification

Rule

Title

Suspicious Shell Open Command Registry Modification

Status

experimental

Level

medium

Author

Swachchhanda Shrawan Poudel (Nextron Systems)

Date

2026-01-24

File

rules/windows/registry/registry_set/registry_set_susp_shell_open_keys_modification_patterns.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects modifications to shell open registry keys that point to suspicious locations typically used by malware for persistence.
Generally, modifications to the `*\shell\open\command` registry key can indicate an attempt to change the default action for opening files,
and various UAC bypass or persistence techniques involve modifying these keys to execute malicious scripts or binaries.

Log source

product

windows

category

registry_set

Detection

selection:
    TargetObject|contains: '\shell\open\command\'
    Details|contains:
        - '\$Recycle.Bin\'
        - '\AppData\Local\Temp\'
        - '\Contacts\'
        - '\Music\'
        - '\PerfLogs\'
        - '\Photos\'
        - '\Pictures\'
        - '\Users\Public\'
        - '\Videos\'
        - '\Windows\Temp\'
        - '%AppData%'
        - '%LocalAppData%'
        - '%Temp%'
        - '%tmp%'
condition: selection

False positives (as the rule lists them)

• Legitimate software installations or updates that modify the shell open command registry keys to these locations.

Tags

• attack.privilege-escalation
• attack.persistence
• attack.t1548.002
• attack.t1546.001

MITRE ATT&CK ids this rule names

• T1546.001
• T1548.002

References

• https://www.trendmicro.com/en_us/research/25/f/water-curse.html

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/registry/registry_set/registry_set_susp_shell_open_keys_modification_patterns.yml