Detection rules › Sigma

User files dump via network share (DonPapi, Lazagne)

Status
experimental
Severity
high
Time window
5m
Log source
product windows, service security
Author
mdecrevoisier
Source
github.com/mdecrevoisier/SIGMA-detection-rules

Detects scenarios where an attacker attempt to dump user profile information via network share.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1555 Credentials from Password Stores

Event coverage

Rule body yaml

title: User files dump via network share (DonPapi, Lazagne)
description: Detects scenarios where an attacker attempt to dump user profile information via network share.
references:
- https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0006-Credential%20Access/T1555-Credentials%20from%20Password%20Stores
- https://github.com/login-securite/DonPAPI
tags:
- attack.credential_access
- attack.t1555
author: mdecrevoisier
status: experimental
logsource:
  product: windows
  service: security
detection:
  selection:
    EventID: 5145
    ShareName: '\\*\C$'
    RelativeTargetName|re:
      - Users\\.*\\Desktop.*
      - Users\\.*\\Recent.*
      - Users\\.*\\Downloads.*
      #- Users\\.* # More broader filter
  filter:
    - RelativeTargetName|re: Users\\.*\\AppData\\.* # handled in another rule
    - IpAddress:
      - '%vulnerability_scanners%'
      - '%admin_netork_administration%'
  condition: selection and not filter | count(RelativeTargetName) by Computer > 15 # Counting over different user names in the path can also decrease false positives
  timeframe: 5m
falsepositives:
- Roaming user profile, vulnerability scanners
level: high

Stages and Predicates

Stage 0: condition

selection and not filter | count(RelativeTargetName) by Computer > 15 # Counting over different user names in the path can also decrease false positives

Stage 1: selection

selection:
  EventID: 5145
  ShareName: '\\*\C$'
  RelativeTargetName|re:
    - Users\\.*\\Desktop.*
    - Users\\.*\\Recent.*
    - Users\\.*\\Downloads.*
Threshold
> 15

Stage 2: not filter

filter:
  - RelativeTargetName|re: Users\\.*\\AppData\\.*
  - IpAddress:
    - '%vulnerability_scanners%'
    - '%admin_netork_administration%'

Exclusions

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

FieldKindExcluded values
IpAddresseq%admin_netork_administration%
IpAddresseq%vulnerability_scanners%
RelativeTargetNameregex_matchUsers\.*\AppData\.*

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
RelativeTargetNameregex_match
  • Users\.*\Desktop.*
  • Users\.*\Downloads.*
  • Users\.*\Recent.*
ShareNamewildcard
  • \\*\C$ corpus 7 (sigma 7)