Ursnif Malware C2 URL Pattern

title: Ursnif Malware C2 URL Pattern
id: 932ac737-33ca-4afd-9869-0d48b391fcc9
status: stable
description: Detects Ursnif C2 traffic.
references:
    - https://www.fortinet.com/blog/threat-research/ursnif-variant-spreading-word-document.html
author: Thomas Patzke
date: 2019-12-19
modified: 2021-08-09
tags:
    - attack.initial-access
    - attack.t1566.001
    - attack.execution
    - attack.t1204.002
    - attack.command-and-control
    - attack.t1071.001
    - detection.emerging-threats
logsource:
    category: proxy
detection:
    b64encoding:
        c-uri|contains:
            - '_2f'
            - '_2b'
    urlpatterns:
        c-uri|contains|all:
            - '.avi'
            - '/images/'
    condition: b64encoding and urlpatterns
falsepositives:
    - Unknown
level: critical