Attachment: CVE-2023-21716 - Microsoft Office Remote Code Execution Vulnerability
Attachment contains an RTF file with a font table defining an excessive number of fonts, used to exploit CVE-2023-21716.
Sublime rule (View on GitHub)
1name: "Attachment: CVE-2023-21716 - Microsoft Office Remote Code Execution Vulnerability"
2description: |
3 Attachment contains an RTF file with a font table defining an excessive number of fonts, used to exploit CVE-2023-21716.
4references:
5 - "https://delivr.to/payloads?id=0a465e03-82a7-42c1-9ded-b0b6b046c86d"
6 - "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-21716"
7 - "https://twitter.com/jduck/status/1632471544935923712"
8 - "https://github.com/gyaansastra/CVE-2023-21716"
9type: "rule"
10severity: "high"
11source: |
12 type.inbound
13 and any(attachments,
14 (
15 .file_extension in~ ("rtf", "doc", "docx")
16 or .file_extension in~ $file_extensions_common_archives
17 or .file_extension in~ $file_extensions_macros
18 )
19 and any(file.explode(.),
20 any(.scan.strings.strings, strings.ilike(., '*\fonttbl*'))
21 and length(filter(.scan.strings.strings, strings.ilike(., '{\f*;}'))) > 10000
22 )
23 )
24attack_types:
25 - "Malware/Ransomware"
26tactics_and_techniques:
27 - "Exploit"
28detection_methods:
29 - "Content analysis"
30 - "File analysis"
31id: "23714cca-f0c6-5fa5-a68b-98c9d60a508d"