Detection rules › Sigma

Publisher Attachment File Dropped In Suspicious Location

Status
test
Severity
medium
Log source
product windows, category file_event
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects creation of files with the ".pub" extension in suspicious or uncommon locations. This could be a sign of attackers abusing Publisher documents

MITRE ATT&CK coverage

TacticTechniques
StealthNo specific technique

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: Publisher Attachment File Dropped In Suspicious Location
id: 3d2a2d59-929c-4b78-8c1a-145dfe9e07b1
status: test
description: Detects creation of files with the ".pub" extension in suspicious or uncommon locations. This could be a sign of attackers abusing Publisher documents
references:
    - https://twitter.com/EmericNasi/status/1623224526220804098
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-02-08
tags:
    - attack.stealth
logsource:
    category: file_event
    product: windows
detection:
    selection:
        TargetFilename|contains:
            - '\AppData\Local\Temp\'
            - '\Users\Public\'
            - '\Windows\Temp\'
            - 'C:\Temp\'
        TargetFilename|endswith: '.pub'
    condition: selection
falsepositives:
    - Legitimate usage of ".pub" files from those locations
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|contains:
        - '\AppData\Local\Temp\'
        - '\Users\Public\'
        - '\Windows\Temp\'
        - 'C:\Temp\'
    TargetFilename|endswith: '.pub'

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
  • .pub
TargetFilenamematch
  • C:\Temp\
  • \AppData\Local\Temp\ corpus 8 (sigma 8)
  • \Users\Public\ corpus 2 (sigma 2)
  • \Windows\Temp\ corpus 2 (sigma 2)