Malicious Office (OOXML) — malware analysis report

Static analysis result for SHA-256 a87d783e0cfb07dc…

MALICIOUS

Office (OOXML)

125.2 KB Created: 2021-07-26 05:40:00 UTC Authoring application: Microsoft Office Word 16.0000
MD5: 8c85601be0a405786745850656b2924b SHA-1: 640d3273d911743afb06442deb91919bdc3baa3a SHA-256: a87d783e0cfb07dc7625e403496a25aedcacf8c305724432345195ea97b11308
242 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1566.001 Spearphishing Attachment

The sample is a malicious OOXML document containing an obfuscated VBA macro with a Document_Open auto-execution routine. The macro concatenates strings to form a URL, likely to download and execute a second-stage payload. The presence of CreateObject and CallByName calls further indicates malicious intent.

Heuristics 8

  • 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.
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present
  • Remote image (web beacon / tracking pixel) medium OOXML_IMAGE_BEACON
    Document references an external image URL — loads automatically on open, revealing IP address and timestamp to the server (used for phishing tracking and NTLM hash theft on corporate networks)
  • External relationship medium OOXML_EXTERNAL_REL
    External target in word/_rels/document.xml.rels: https://divine-bar-3d75.visual-candy.workers.dev/blackhole.png
  • 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.microsoft.com/office/drawing/2014/chartex
    • http://schemas.microsoft.com/office/drawing/2015/9/8/chartex
    • 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/2012/wordml
    • http://schemas.microsoft.com/office/word/2015/wordml/symex
    • 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
    • https://divine-bar-3d75.visual-candy.workers.dev/blackhole.png

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
b1d6bacc1d784e7b67bd27d4555507ca6dcd49db2db6183e25e82f726b280365		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 117097 bytes
vbaProject_00.bin
33c397155f954b502c52d2e898be14ec71ea8a3ede034f2581abcc521fe126ef		 vba-project OOXML VBA project: word/vbaProject.bin 115200 bytes

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