Process Reimaging

The Windows Operating System has inconsistencies in how it determines process image FILE_OBJECT locations, which impacts non-EDR (Endpoint Detection and Response) Endpoint Security Solution’s (such as Microsoft Defender Realtime Protection), ability to detect the correct binaries loaded in malicious processes.

This inconsistency has led McAfee’s Advanced Threat Research to develop a new post-exploitation evasion technique called “Process Reimaging”. This technique is equivalent in impact to Process Hollowing or Process Doppelganging within the Mitre Attack Defense Evasion Category; however, it is , much easier to execute as it requires no code injection.

While this bypass has been successfully tested against current versions of Microsoft Windows and Defender, it is highly likely that the bypass will work on any endpoint security vendor or product implementing the APIs discussed below.

U1210

Detection Rules

action: global
title: Defense evasion via process reimaging
id: 7fa4f550-850e-4117-b543-428c86ebb849
description: Detects process reimaging defense evasion technique
status: experimental
author: Alexey Balandin, oscd.community
references:
    - https://securingtomorrow.mcafee.com/other-blogs/mcafee-labs/in-ntdll-i-trust-process-reimaging-and-endpoint-security-solution-bypass/
tags:
    - attack.defense_evasion
date: 2019/10/25
detection:
    condition: all of them
falsepositives:
    - unknown
level: high
---
logsource:
    product: windows
    service: sysmon
detection:
    selection1:
        category: process_creation
fields:
    - Image
    - OriginalFileName
    - ParentProcessGuid
new_fields:
    - ImageFileName
---
logsource:
    product: windows
    service: sysmon
detection:
    selection2:
        EventID: 11
fields:
    - ProcessGuid
    - TargetFilename

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