Outbound Network Connection Initiated By Script Interpreter

calendar Aug 12, 2024 · attack.command-and-control attack.t1105  ·
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Detects a script interpreter wscript/cscript opening a network connection to a non-local network. Adversaries may use script to download malicious payloads.

Sigma rule (View on GitHub)

 1title: Outbound Network Connection Initiated By Script Interpreter
 2id: 992a6cae-db6a-43c8-9cec-76d7195c96fc
 3related:
 4    - id: 08249dc0-a28d-4555-8ba5-9255a198e08c
 5      type: derived
 6status: test
 7description: Detects a script interpreter wscript/cscript opening a network connection to a non-local network. Adversaries may use script to download malicious payloads.
 8references:
 9    - https://github.com/redcanaryco/atomic-red-team/blob/28d190330fe44de6ff4767fc400cc10fa7cd6540/atomics/T1105/T1105.md
10author: frack113, Florian Roth (Nextron Systems)
11date: 2022-08-28
12modified: 2024-03-13
13tags:
14    - attack.command-and-control
15    - attack.t1105
16logsource:
17    category: network_connection
18    product: windows
19detection:
20    selection:
21        Initiated: 'true'
22        Image|endswith:
23            - '\wscript.exe'
24            - '\cscript.exe'
25    filter_main_local_ranges:
26        DestinationIp|cidr:
27            - '127.0.0.0/8'
28            - '10.0.0.0/8'
29            - '172.16.0.0/12'
30            - '192.168.0.0/16'
31            - '169.254.0.0/16'
32            - '::1/128'  # IPv6 loopback
33            - 'fe80::/10'  # IPv6 link-local addresses
34            - 'fc00::/7'  # IPv6 private addresses
35    filter_main_ms_ranges:
36        DestinationIp|cidr: '20.0.0.0/11' # Microsoft range, caused some FPs
37    condition: selection and not 1 of filter_main_*
38falsepositives:
39    - Legitimate scripts
40level: high

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