Registry Modification for OCI DLL Redirection

SIGMA detection rule by Swachchhanda Shrawan Poudel (Nextron Systems) · NOASSERTION

Detects registry modifications related to 'OracleOciLib' and 'OracleOciLibPath' under 'MSDTC' settings. Threat actors may modify these registry keys to redirect the loading of 'oci.dll' to a malicious DLL, facilitating phantom DLL hijacking via the MSDTC service.

title: Registry Modification for OCI DLL Redirection
id: c0e0bdec-3e3d-47aa-9974-05539c999c89
status: experimental
description: |
    Detects registry modifications related to 'OracleOciLib' and 'OracleOciLibPath' under 'MSDTC' settings.
    Threat actors may modify these registry keys to redirect the loading of 'oci.dll' to a malicious DLL, facilitating phantom DLL hijacking via the MSDTC service.
references:
    - https://www.crowdstrike.com/en-us/blog/4-ways-adversaries-hijack-dlls/
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2026-01-24
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.defense-impairment
    - attack.t1112
    - attack.t1574.001
logsource:
    category: registry_set
    product: windows
detection:
    selection_ocilib:
        TargetObject|endswith: '\SOFTWARE\Microsoft\MSDTC\MTxOCI\OracleOciLib'
    filter_main_ocilib_file:
        # it is looking when oci.dll name is changed to something else like evil.dll
        Details|contains: 'oci.dll'
    selection_ocilibpath:
        TargetObject|endswith: '\SOFTWARE\Microsoft\MSDTC\MTxOCI\OracleOciLibPath'
    filter_main_ocilibpath:
        # it is looking when oci.dll path is changed to something else like 'C:\Windows\Temp\'
        Details|contains: '%SystemRoot%\System32\'
    condition: (selection_ocilib and not filter_main_ocilib_file) or (selection_ocilibpath and not filter_main_ocilibpath)
falsepositives:
    - Unlikely
level: high

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

1eaacefb-edea-48a1-9e0c-abf964cc5ec1

Propose edits, view related rules, and engage with the community through comments.

Executable code, not a declarative rule

This submission is arbitrary [[ currentRule.format ? currentRule.format.toUpperCase() : '' ]] code, not a declarative detection rule — review it as you would any script before running it, and note that it cannot be safely aggregated or auto-executed alongside YARA/Sigma/Suricata/CRS rules.

Rejected pattern present

[[ reason ]]

What does this mean?

Format & documentation suggestions

Not a security issue — this rule is valid and was accepted as-is. These are optional fields/conventions its own format recommends, mainly affecting its quality score and how well it documents itself for other reviewers.

[[ reason ]]

What do these messages mean?

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

[[ currentRule.title ]]

Community Discussion