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

Static analysis result for SHA-256 3b86f8aff12d2b32…

MALICIOUS

Office (OOXML) / .DOC

2.19 MB Created: 2022-08-11 15:08:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2022-08-11
MD5: 2b10f2617b32857999df1cf5f19f0d8d SHA-1: 448e513536aa0c576b123d5b243e1bdc6d261d6f SHA-256: 3b86f8aff12d2b32461a0b20f01f3d13ee062c80cb647ce09ff33f296b1f9e47
362 Risk Score

Malware Insights

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

The sample is an OOXML document containing a VBA project with a renamed part to evade detection. It utilizes a Document_Open macro that employs GetObject and CallByName functions, indicative of a shellcode loader. The macro reads configuration from reversed document properties and uses VirtualProtect to execute shellcode in memory, a common technique for downloading and executing second-stage payloads. The document body explicitly instructs the user to 'Enable editing' and 'Enable content', a social engineering lure to bypass macro security.

Heuristics 10

  • VBA property-stored shellcode loader critical OLE_VBA_PROPERTY_SHELLCODE_LOADER
    VBA auto-exec macro takes the address (VarPtr) of a byte buffer decoded from a document property, marks memory executable (VirtualProtect/VirtualAlloc), and transfers control through a callback API (e.g. SetTimer/EnumWindows). The payload is hidden in the document properties rather than the macro source — the SVCReady loader pattern, a native shellcode runner rather than a parser CVE.
  • ClamAV: Doc.Downloader.af2f0393915c6ce8-OOXML-9981526-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.af2f0393915c6ce8-OOXML-9981526-0
  • VBA project part renamed to evade filename detection high OOXML_VBA_PROJECT_RENAMED
    The VBA project is bound through the OOXML relationship/content type but its part is not named vbaProject.bin. Legitimate Office producers always emit vbaProject.bin; renaming it hides the macros from path-only scanners (observed in the SVCReady loader).
  • Document_Open macro high OLE_VBA_DOCOPEN
    Document_Open macro
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • CallByName call high OLE_VBA_CALLBYNAME
    CallByName call
  • VBA reads reversed config from document properties high OLE_VBA_REVERSED_DOCPROP_CONFIG
    VBA applies StrReverse to values read from the document's custom/built-in properties. Storing reversed configuration (URLs, CLSIDs, env-var names, payload names) in document properties keeps indicators out of the macro source — an obfuscation technique used by the SVCReady loader.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — VBA macros present (project part renamed away from vbaProject.bin: word/txrPBKwdQu.bin)
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings
  • 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
7dce4b44d702bfe333d8904aeac177eab107ad99cdfe3cf3fdc47e35d4fab467		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 21347 bytes
vbaProject_00.bin
451314d919aff6eedc2a34ea73650e6ffa6af589edea221c74639218c094f7e1		 vba-project OOXML VBA project: word/txrPBKwdQu.bin 14848 bytes

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