Malicious Office (OOXML) / .DOC — malware analysis report

Static analysis result for SHA-256 578a35e36d8e6a93…

MALICIOUS

Office (OOXML) / .DOC

867.2 KB Created: 2022-09-26 12:15:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2022-09-26
MD5: e9d1cfdbc9395de2b84a4ed5094a1797 SHA-1: 8bafd22f6140314c62f5e75b5d8360c59fa889b7 SHA-256: 578a35e36d8e6a9328cec388852679bac9c7fc9d1cb60a6350ebd9f6a65cc563
342 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is an Office document containing a VBA macro with an auto-exec loader. The macro utilizes obfuscated code and calls to `CreateObject` and `Shell()` functions, indicating an intent to download and execute a second-stage payload. ClamAV detections confirm the malicious nature, identifying it as 'Xls.Dropper.Valyria-10012499-0', a known dropper.

Heuristics 8

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Xls.Dropper.Valyria-10012499-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Valyria-10012499-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • 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://schemas.microsoft.com/office/word/2010/wordprocessingCanvas
    • http://schemas.openxmlformats.org/markup-compatibility/2006
    • http://schemas.openxmlformats.org/officeDocument/2006/relationships
    • http://schemas.openxmlformats.org/officeDocument/2006/math
    • http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing
    • http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing
    • http://schemas.openxmlformats.org/wordprocessingml/2006/main
    • http://schemas.microsoft.com/office/word/2010/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingGroup
    • http://schemas.microsoft.com/office/word/2010/wordprocessingInk
    • http://schemas.microsoft.com/office/word/2006/wordml
    • http://schemas.microsoft.com/office/word/2010/wordprocessingShape

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
840cf476aa99672b7979c294157930b738f94b12581d2dd05d7d251925c3cfba		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 30857 bytes
vbaProject_00.bin
f80bafb3999623a612c210750f7020fef5c27279eefede0bfba6969454a1aae9		 vba-project OOXML VBA project: word/vbaProject.bin 34304 bytes
Detection
ClamAV: Xls.Dropper.Valyria-10012499-0
Obfuscation or payload: unlikely

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