Internet Explorer Autorun Keys Modification

Hunt Hypothesis

Detects modification of autostart extensibility point (ASEP) in registry.

Detection Rule

Sigma (Original)

title: Internet Explorer Autorun Keys Modification
id: a80f662f-022f-4429-9b8c-b1a41aaa6688
related:
    - id: 17f878b8-9968-4578-b814-c4217fc5768c
      type: obsolete
status: test
description: Detects modification of autostart extensibility point (ASEP) in registry.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1547.001/T1547.001.md
    - https://learn.microsoft.com/en-us/sysinternals/downloads/autoruns
    - https://gist.github.com/GlebSukhodolskiy/0fc5fa5f482903064b448890db1eaf9d # a list with registry keys
author: Victor Sergeev, Daniil Yugoslavskiy, Gleb Sukhodolskiy, Timur Zinniatullin, oscd.community, Tim Shelton, frack113 (split)
date: 2019-10-25
modified: 2023-08-17
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1547.001
logsource:
    category: registry_set
    product: windows
detection:
    ie:
        TargetObject|contains:
            - '\Software\Wow6432Node\Microsoft\Internet Explorer'
            - '\Software\Microsoft\Internet Explorer'
    ie_details:
        TargetObject|contains:
            - '\Toolbar'
            - '\Extensions'
            - '\Explorer Bars'
    filter_empty:
        Details: '(Empty)'
    filter_extensions:
        TargetObject|contains:
            - '\Extensions\{2670000A-7350-4f3c-8081-5663EE0C6C49}'
            - '\Extensions\{31D09BA0-12F5-4CCE-BE8A-2923E76605DA}'
            - '\Extensions\{789FE86F-6FC4-46A1-9849-EDE0DB0C95CA}'
            - '\Extensions\{A95fe080-8f5d-11d2-a20b-00aa003c157a}'
    filter_toolbar:
        TargetObject|endswith:
            - '\Toolbar\ShellBrowser\ITBar7Layout'
            - '\Toolbar\ShowDiscussionButton'
            - '\Toolbar\Locked'
    condition: ie and ie_details and not 1 of filter_*
falsepositives:
    - Legitimate software automatically (mostly, during installation) sets up autorun keys for legitimate reason
    - Legitimate administrator sets up autorun keys for legitimate reason
level: medium

KQL (Azure Sentinel)

imRegistry
| where (RegistryKey contains "\\Software\\Wow6432Node\\Microsoft\\Internet Explorer" or RegistryKey contains "\\Software\\Microsoft\\Internet Explorer") and (RegistryKey contains "\\Toolbar" or RegistryKey contains "\\Extensions" or RegistryKey contains "\\Explorer Bars") and (not((RegistryValueData =~ "(Empty)" or (RegistryKey contains "\\Extensions\\{2670000A-7350-4f3c-8081-5663EE0C6C49}" or RegistryKey contains "\\Extensions\\{31D09BA0-12F5-4CCE-BE8A-2923E76605DA}" or RegistryKey contains "\\Extensions\\{789FE86F-6FC4-46A1-9849-EDE0DB0C95CA}" or RegistryKey contains "\\Extensions\\{A95fe080-8f5d-11d2-a20b-00aa003c157a}") or (RegistryKey endswith "\\Toolbar\\ShellBrowser\\ITBar7Layout" or RegistryKey endswith "\\Toolbar\\ShowDiscussionButton" or RegistryKey endswith "\\Toolbar\\Locked"))))

KQL (Microsoft 365 Defender)

DeviceRegistryEvents
| where (RegistryKey contains "\\Software\\Wow6432Node\\Microsoft\\Internet Explorer" or RegistryKey contains "\\Software\\Microsoft\\Internet Explorer") and (RegistryKey contains "\\Toolbar" or RegistryKey contains "\\Extensions" or RegistryKey contains "\\Explorer Bars") and (not((RegistryValueData =~ "(Empty)" or (RegistryKey contains "\\Extensions\\{2670000A-7350-4f3c-8081-5663EE0C6C49}" or RegistryKey contains "\\Extensions\\{31D09BA0-12F5-4CCE-BE8A-2923E76605DA}" or RegistryKey contains "\\Extensions\\{789FE86F-6FC4-46A1-9849-EDE0DB0C95CA}" or RegistryKey contains "\\Extensions\\{A95fe080-8f5d-11d2-a20b-00aa003c157a}") or (RegistryKey endswith "\\Toolbar\\ShellBrowser\\ITBar7Layout" or RegistryKey endswith "\\Toolbar\\ShowDiscussionButton" or RegistryKey endswith "\\Toolbar\\Locked"))))

Required Data Sources

False Positive Guidance

• Legitimate software automatically (mostly, during installation) sets up autorun keys for legitimate reason
• Legitimate administrator sets up autorun keys for legitimate reason

MITRE ATT&CK Context

• Tactic: Privilege Escalation
• Tactic: Persistence
• Technique: T1547.001 — T1547.001

References

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1547.001/T1547.001.md
• https://learn.microsoft.com/en-us/sysinternals/downloads/autoruns
• https://gist.github.com/GlebSukhodolskiy/0fc5fa5f482903064b448890db1eaf9d
• SigmaHQ Rule