Sigma rule: Potential Persistence Via Custom Protocol Handler

Rule

Title

Potential Persistence Via Custom Protocol Handler

Status

test

Level

medium

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2022-05-30

Modified

2023-05-12

File

rules/windows/registry/registry_set/registry_set_persistence_custom_protocol_handler.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects potential persistence activity via the registering of a new custom protocole handlers. While legitimate applications register protocole handlers often times during installation. And attacker can abuse this by setting a custom handler to be used as a persistence mechanism.

Log source

product

windows

category

registry_set

Detection

selection:
    TargetObject|startswith: 'HKCR\'
    Details|startswith: 'URL:'
filter_main_ms_trusted:
    Details|startswith: 'URL:ms-' # Microsoft Protocols usually start with "ms-"
filter_main_generic_locations:
    Image|startswith: # Add more folders to avoid FP
        - 'C:\Program Files (x86)'
        - 'C:\Program Files\'
        - 'C:\Windows\System32\'
        - 'C:\Windows\SysWOW64\'
# Uncomment This section to add specific Protocol Handler names that are know
# filter_specific:
#     Details: 'URL:'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Many legitimate applications can register a new custom protocol handler. Additional filters needs to applied according to your environment.

Tags

• attack.persistence
• attack.defense-impairment
• attack.t1112

MITRE ATT&CK ids this rule names

• T1112

References

• https://ladydebug.com/blog/2019/06/21/custom-protocol-handler-cph/

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_persistence_custom_protocol_handler.yml