title: DNS RCE CVE-2020-1350
id: b5281f31-f9cc-4d0d-95d0-45b91c45b487
status: test
description: Detects exploitation of DNS RCE bug reported in CVE-2020-1350 by the detection of suspicious sub process
references:
    - https://research.checkpoint.com/2020/resolving-your-way-into-domain-admin-exploiting-a-17-year-old-bug-in-windows-dns-servers/
    - https://web.archive.org/web/20230329172447/https://blog.menasec.net/2019/02/threat-hunting-24-microsoft-windows-dns.html
author: Florian Roth (Nextron Systems)
date: 2020-07-15
modified: 2022-07-12
tags:
    - attack.initial-access
    - attack.t1190
    - attack.execution
    - attack.t1569.002
    - cve.2020-1350
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\System32\dns.exe'
    filter:
        Image|endswith:
            - '\System32\werfault.exe'
            - '\System32\conhost.exe'
            - '\System32\dnscmd.exe'
            - '\System32\dns.exe'
    condition: selection and not filter
falsepositives:
    - Unknown but benign sub processes of the Windows DNS service dns.exe
level: critical

title: Unusual File Deletion by Dns.exe
id: 8f0b1fb1-9bd4-4e74-8cdf-a8de4d2adfd0
related:
    - id: 9f383dc0-fdeb-4d56-acbc-9f9f4f8f20f3 # FileChange version
      type: similar
status: test
description: Detects an unexpected file being deleted by dns.exe which my indicate activity related to remote code execution or other forms of exploitation as seen in CVE-2020-1350 (SigRed)
references:
    - https://www.elastic.co/guide/en/security/current/unusual-file-modification-by-dns-exe.html
author: Tim Rauch (Nextron Systems), Elastic (idea)
date: 2022-09-27
modified: 2023-02-15
tags:
    - attack.persistence
    - attack.initial-access
    - attack.t1133
logsource:
    category: file_delete
    product: windows
detection:
    selection:
        Image|endswith: '\dns.exe'
    filter:
        TargetFilename|endswith: '\dns.log'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

title: Unusual File Modification by dns.exe
id: 9f383dc0-fdeb-4d56-acbc-9f9f4f8f20f3
related:
    - id: 8f0b1fb1-9bd4-4e74-8cdf-a8de4d2adfd0 # FileDelete version
      type: similar
status: test
description: Detects an unexpected file being modified by dns.exe which my indicate activity related to remote code execution or other forms of exploitation as seen in CVE-2020-1350 (SigRed)
references:
    - https://www.elastic.co/guide/en/security/current/unusual-file-modification-by-dns-exe.html
author: Tim Rauch (Nextron Systems), Elastic (idea)
date: 2022-09-27
tags:
    - attack.persistence
    - attack.initial-access
    - attack.t1133
logsource:
    category: file_change
    product: windows
detection:
    selection:
        Image|endswith: '\dns.exe'
    filter:
        TargetFilename|endswith: '\dns.log'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high

title: Unusual Child Process of dns.exe
id: a4e3d776-f12e-42c2-8510-9e6ed1f43ec3
status: test
description: Detects an unexpected process spawning from dns.exe which may indicate activity related to remote code execution or other forms of exploitation as seen in CVE-2020-1350 (SigRed)
references:
    - https://www.elastic.co/guide/en/security/current/unusual-child-process-of-dns-exe.html
author: Tim Rauch, Elastic (idea)
date: 2022-09-27
modified: 2023-02-05
tags:
    - attack.persistence
    - attack.initial-access
    - attack.t1133
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\dns.exe'
    filter:
        Image|endswith: '\conhost.exe'
    condition: selection and not filter
falsepositives:
    - Unknown
level: high