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

Static analysis result for SHA-256 10c00de5df9f12d5…

MALICIOUS

Office (OOXML) / .DOC

866.1 KB Created: 2022-09-26 12:15:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2022-09-26
MD5: bc56cd4b450e2e765c83a5a5260a7f14 SHA-1: 4f71714b7208ca4dac5a57f68281245ae629cbc6 SHA-256: 10c00de5df9f12d59e7113dfac0618f26a8b16a19312c576c616ac757e4448e5
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 contains a heavily obfuscated VBA macro with an auto-exec loader, indicative of a dropper. The macro utilizes `CreateObject` and `Shell()` calls, suggesting it attempts to download and execute a secondary payload. ClamAV detection confirms this, identifying it as 'Xls.Dropper.Valyria-10012499-0'. The VBA code appears to be a custom decoder for obfuscated strings, likely containing URLs or commands for the payload.

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
4018352881d8fd3979a68010afa2146f8635dcd47e8a60d6f78d0b2c13170a32		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 30645 bytes
vbaProject_00.bin
128bc19e3cf1878d8718f427a695defac92c6e544a0b96f9272e265819979a64		 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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