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

Static analysis result for SHA-256 04042893124fdbf0…

MALICIOUS

Office (OOXML) / .DOC

2.21 MB Created: 2022-08-11 14:51:00 UTC Authoring application: Microsoft Office Word 14.0000 First seen: 2022-08-11
MD5: 13f0a9bd5a2a4fd90924a953eb9b1642 SHA-1: bb6d3ab2c01d3058964cd6493a691ad9971307ca SHA-256: 04042893124fdbf007cfdb673ef878ac9a47f37f871c1e5322ec46945915abc1
362 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1140 Deobfuscate or Obfuscate Malicious Code

The sample is an OOXML document containing a VBA project with a renamed part to evade detection. It utilizes a Document_Open macro, GetObject, and CallByName functions, indicative of a downloader. The critical heuristic 'OLE_VBA_PROPERTY_SHELLCODE_LOADER' suggests the macro loads and executes shellcode, likely from document properties, as hinted by 'OLE_VBA_REVERSED_DOCPROP_CONFIG'. The embedded VBA script, though truncated, shows obfuscated API calls and a function 'OSxlmNJ3q' that reverses strings from custom document properties, confirming the shellcode loader mechanism.

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/gSZKVxnIuW.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
b1a478a77ce68579f75c9bc0883c8ef12e77802212ca71210dce44bca721653c		 vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 20890 bytes
vbaProject_00.bin
a3c3545e55f3dd0293881e1d947f09ea0fdb7ce719ae746285b9fd6bf0d73472		 vba-project OOXML VBA project: word/gSZKVxnIuW.bin 14848 bytes

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