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

Static analysis result for SHA-256 bc45389ee9779bf1…

MALICIOUS

Office (OOXML) / .DOC

2.21 MB Created: 2022-08-11 14:32:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2022-08-11
MD5: 4b1f44814b6cb058b041c39702c8d6a0 SHA-1: 89ec91828cb944e48804aa31293cda0e2d16cda8 SHA-256: bc45389ee9779bf1c6ad66d8b25b4032212fbd5db0defd2e5443a27c1b7a4e80
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 project part to evade detection. It utilizes a Document_Open macro that acts as a shellcode loader, reading configuration from document properties and executing it in memory. The document body contains a lure to enable macros, a common tactic for macro-based downloaders.

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.8a5a5aca5aca5a7a-OOXML-9981537-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.8a5a5aca5aca5a7a-OOXML-9981537-0
  • 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/cdzWCPZfKt.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
8d912919843267bbcf4e5027f06919f9099eb80ae7fd6e7724bee76afaa6476c		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 19787 bytes
vbaProject_00.bin
ecd1c2fcfaa3083cf4cd6261792423a4909f487c9099962a10bbefe7130c9f74		 vba-project OOXML VBA project: word/cdzWCPZfKt.bin 14848 bytes

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