YARA · Signature Base (Florian Roth / Nextron)
SIGNATURE_BASE_HKTL_EXPL_POC_NET_Sharepoint_CVE_2023_29357_Sep23_1
Detects a C# POC to exploit CVE-2023-29357 on Microsoft SharePoint servers
- Author
- Florian Roth
- Date
- 2023-10-01
- Modified
- 2023-12-05
- Score / Quality
- 80 / 85
What this rule detects
Detects a C# POC to exploit CVE-2023-29357 on Microsoft SharePoint servers
Targets: Windows PE.
It defines 8 patterns (8 text, 0 hex, 0 regex).
Summary generated from the rule's metadata and condition.
Rule source
hktl-expl-poc-net-sharepoint-cve-2023-29357-sep23-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_HKTL_EXPL_POC_NET_Sharepoint_CVE_2023_29357_Sep23_1 : CVE_2023_29357 FILE
{
meta:
= "Detects a C# POC to exploit CVE-2023-29357 on Microsoft SharePoint servers"
= "Florian Roth"
= "aa6aeb00-b162-538c-a670-cbff525dd8f1"
= "2023-10-01"
= "2023-12-05"
= "https://github.com/LuemmelSec/CVE-2023-29357"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/expl_sharepoint_cve_2023_29357.yar#L37-L62"
= "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
= "cf621cc9c5074f531df61623b09db68478e94ae6a9a7acc26aa8d9dde79bd30c"
= 80
= 85
= "CVE-2023-29357, FILE"
strings:
$x1 = "{f22d2de0-606b-4d16-98d5-421f3f1ba8bc}" ascii wide
$x2 = "{F22D2DE0-606B-4D16-98D5-421F3F1BA8BC}" ascii wide
$s1 = "Bearer"
$s2 = "hashedprooftoken"
$s3 = "/_api/web/"
$s4 = "X-PROOF_TOKEN"
$s5 = "00000003-0000-0ff1-ce00-000000000000"
$s6 = "IsSiteAdmin"
condition:
uint16( 0 ) == 0x5a4d and filesize < 800KB and ( 1 of ( $x* ) or all of ( $s* ) )
}
Strings (8 patterns)
| Identifier | Type | Value | Modifiers |
|---|---|---|---|
| $x1 | text | "{f22d2de0-606b-4d16-98d5-421f3f1ba8bc}" | ascii wide |
| $x2 | text | "{F22D2DE0-606B-4D16-98D5-421F3F1BA8BC}" | ascii wide |
| $s1 | text | "Bearer" | |
| $s2 | text | "hashedprooftoken" | |
| $s3 | text | "/_api/web/" | |
| $s4 | text | "X-PROOF_TOKEN" | |
| $s5 | text | "00000003-0000-0ff1-ce00-000000000000" | |
| $s6 | text | "IsSiteAdmin" |
Condition
uint16( 0 ) == 0x5a4d and filesize < 800KB and ( 1 of ( $x* ) or all of ( $s* ) )In plain words (Heuristic)
- The file must start with “MZ” — a Windows executable (PE).
- The file must be smaller than 800KB (a cheap guard that skips large files).
- All patterns in ( $s* ) must match.
- At least 1 patterns in ( $x* ) must match.
Test this rule in your browser
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Licence & attribution
Author: Florian Roth
Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a
Licence: Detection Rule License 1.1 (repository licence)
Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.
Rule id: aa6aeb00-b162-538c-a670-cbff525dd8f1
Tags:CVE_2023_29357FILE
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