File Download From Browser Process Via Inline URL

calendar Nov 14, 2023 · attack.command_and_control attack.t1105  ·
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Detects execution of a browser process with a URL argument pointing to a file with a potentially interesting extension. This can be abused to download arbitrary files or to hide from the user for example by launching the browser in a minimized state.

Sigma rule (View on GitHub)

 1title: File Download From Browser Process Via Inline URL
 2id: 94771a71-ba41-4b6e-a757-b531372eaab6
 3status: test
 4description: Detects execution of a browser process with a URL argument pointing to a file with a potentially interesting extension. This can be abused to download arbitrary files or to hide from the user for example by launching the browser in a minimized state.
 5references:
 6    - https://twitter.com/mrd0x/status/1478116126005641220
 7    - https://lolbas-project.github.io/lolbas/Binaries/Msedge/
 8author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
 9date: 2022/01/11
10modified: 2023/11/09
11tags:
12    - attack.command_and_control
13    - attack.t1105
14logsource:
15    category: process_creation
16    product: windows
17detection:
18    selection_img:
19        Image|endswith:
20            - '\brave.exe'
21            - '\chrome.exe'
22            - '\msedge.exe'
23            - '\opera.exe'
24            - '\vivaldi.exe'
25    selection_http:
26        CommandLine|contains: 'http'
27    selection_extensions:
28        CommandLine|endswith:
29            - '.7z'
30            - '.dat'
31            - '.dll'
32            - '.exe'
33            - '.hta'
34            - '.ps1'
35            - '.psm1'
36            - '.txt'
37            - '.vbe'
38            - '.vbs'
39            - '.zip'
40    condition: all of selection_*
41falsepositives:
42    - Unknown
43level: medium

References

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