Detection rules › Sigma

Suspicious PROCEXP152.sys File Created In TMP

Status
test
Severity
medium
Log source
product windows, category file_event
Author
xknow (@xknow_infosec), xorxes (@xor_xes)
Source
github.com/SigmaHQ/sigma

Detects the creation of the PROCEXP152.sys file in the application-data local temporary folder. This driver is used by Sysinternals Process Explorer but also by KDU (https://github.com/hfiref0x/KDU) or Ghost-In-The-Logs (https://github.com/bats3c/Ghost-In-The-Logs), which uses KDU.

MITRE ATT&CK coverage

TacticTechniques
Defense ImpairmentT1685 Disable or Modify Tools

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: Suspicious PROCEXP152.sys File Created In TMP
id: 3da70954-0f2c-4103-adff-b7440368f50e
status: test
description: |
  Detects the creation of the PROCEXP152.sys file in the application-data local temporary folder.
  This driver is used by Sysinternals Process Explorer but also by KDU (https://github.com/hfiref0x/KDU) or Ghost-In-The-Logs (https://github.com/bats3c/Ghost-In-The-Logs), which uses KDU.
references:
    - https://web.archive.org/web/20230331181619/https://blog.dylan.codes/evading-sysmon-and-windows-event-logging/
author: xknow (@xknow_infosec), xorxes (@xor_xes)
date: 2019-04-08
modified: 2022-11-22
tags:
    - attack.defense-impairment
    - attack.t1685
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|contains: '\AppData\Local\Temp\'
        TargetFilename|endswith: 'PROCEXP152.sys'
    filter:
        Image|contains:
            - '\procexp64.exe'
            - '\procexp.exe'
            - '\procmon64.exe'
            - '\procmon.exe'
    condition: selection and not filter
falsepositives:
    - Other legimate tools using this driver and filename (like Sysinternals). Note - Clever attackers may easily bypass this detection by just renaming the driver filename. Therefore just Medium-level and don't rely on it.
level: medium

Stages and Predicates

Stage 0: condition

selection and not filter

Stage 1: selection

selection:
    TargetFilename|contains: '\AppData\Local\Temp\'
    TargetFilename|endswith: 'PROCEXP152.sys'

Stage 2: not filter

filter:
    Image|contains:
        - '\procexp64.exe'
        - '\procexp.exe'
        - '\procmon64.exe'
        - '\procmon.exe'

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
Imagematch\procexp.exe
Imagematch\procexp64.exe
Imagematch\procmon.exe
Imagematch\procmon64.exe

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
TargetFilenameends_with
  • PROCEXP152.sys
TargetFilenamematch
  • \AppData\Local\Temp\ corpus 8 (sigma 8)