Suspicious Word Cab File Write CVE-2021-40444

calendar Aug 12, 2024 · attack.resource-development attack.t1587 detection.emerging-threats  ·
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Detects file creation patterns noticeable during the exploitation of CVE-2021-40444

Sigma rule (View on GitHub)

 1title: Suspicious Word Cab File Write CVE-2021-40444
 2id: 60c0a111-787a-4e8a-9262-ee485f3ef9d5
 3status: test
 4description: Detects file creation patterns noticeable during the exploitation of CVE-2021-40444
 5references:
 6    - https://twitter.com/RonnyTNL/status/1436334640617373699?s=20
 7    - https://twitter.com/vanitasnk/status/1437329511142420483?s=21
 8author: Florian Roth (Nextron Systems), Sittikorn S
 9date: 2021-09-10
10modified: 2023-06-22
11tags:
12    - attack.resource-development
13    - attack.t1587
14    - detection.emerging-threats
15logsource:
16    product: windows
17    category: file_event
18detection:
19    selection_cab:
20        Image|endswith: '\winword.exe'
21        TargetFilename|contains: '\Windows\INetCache'
22        TargetFilename|endswith: '.cab'
23    selection_inf:
24        Image|endswith: '\winword.exe'
25        TargetFilename|contains|all:
26            - '\AppData\Local\Temp\'
27            - '.inf'
28    filter_main_legit:
29        TargetFilename|startswith: 'C:\Users\'
30        TargetFilename|contains: 'AppData\Local\Temp'
31        TargetFilename|endswith: '\Content.inf'
32    condition: 1 of selection_* and not 1 of filter_main_*
33falsepositives:
34    - Unknown
35level: high

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