FormBook — Office (OOXML) malware analysis

Static analysis result for SHA-256 996c88f99575ab5d…

MALICIOUS

Office (OOXML)

11.8 KB Created: 2017-09-24 17:26:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2019-04-18
MD5: 25a60020fe3eb5d40f5d544543fcb58c SHA-1: b2401ef7942cc91ba87133792d762ef2c79ca0d1 SHA-256: 996c88f99575ab5d784ad3b9fa3fcc75c7450ea4f9de582ce9c7b3d147f7c6d5
142 Risk Score

Malware Insights

FormBook · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV with the signature Win.Trojan.FormBook-6749866-0. Heuristics indicate the exploitation of CVE-2017-0199, which is used to load an external OLE object from the URL http://avast.dongguanmolds.com/plugin.wbk. This suggests the document is designed to download and execute a secondary payload, characteristic of FormBook malware.

Heuristics 4

  • OOXML OLE2Link remote loader — CVE-2017-0199 related high CVE related CVE_2017_0199_RELATED
    Document contains an o:OLEObject Type=Link whose external oleObject relationship points to a remote URL. This is the OOXML OLE2Link activation shape associated with CVE-2017-0199 delivery, but the local file does not expose URL Moniker bytes or a weaponized extension/content type, so the exact CVE cannot be proven statically.
  • ClamAV: Win.Trojan.FormBook-6749866-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.FormBook-6749866-0
  • External OLE object relationship high OOXML_EXTERNAL_OLE_OBJECT
    Document contains an oleObject relationship whose target is an external HTTP(S) URL. Office resolves this through OLE/object update paths rather than as a normal user-clicked hyperlink.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://avast.dongguanmolds.com/plugin.wbk In document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingCanvasIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/markup-compatibility/2006In document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/relationshipsIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/officeDocument/2006/mathIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawingIn document text (OOXML body / shared strings)
    • http://schemas.openxmlformats.org/wordprocessingml/2006/mainIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroupIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInkIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2006/wordmlIn document text (OOXML body / shared strings)
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShapeIn document text (OOXML body / shared strings)

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