Medium Severity
Attachment: Archive with embedded CHM file
Labels
Description
Recursively scans files and archives to detect embedded CHM (Microsoft Compiled HTML Help) files.
According to CERT-UA, on March 7, 2022, phishing attacks targeted state organizations of Ukraine
using Zip files with embedded CHM documents, which themselves contained malicious VBScript inside a .htm file.
The activity is associated with UNC1151, according to CERT-UA.
References
Sublime Security
Created Aug 17th, 2023 • Last updated Aug 21st, 2023
Feed Source
Sublime Core Feed
Source
type.inbound
and any(attachments,
.file_extension in~ $file_extensions_common_archives
and any(file.explode(.), .file_extension =~ "chm")
)
Playground
Test against your own EMLs or sample data.