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

Static analysis result for SHA-256 0fef64eab9583e65…

MALICIOUS

Office (OLE) / .DOC

501.0 KB Created: 2021-12-03 17:38:00 Authoring application: Microsoft Office Word
MD5: 9ca16900f5e47678fe02d5caf0fd1bda SHA-1: 0e099b335bacf41555431c11530ceb46097f0ae8 SHA-256: 0fef64eab9583e653f02f7fc28af21b9cc14265f8a6bbae518e2325d417994cd
280 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059 Command and Scripting Interpreter T1566.001 Spearphishing Attachment

The sample contains a critical heuristic for an obfuscated auto-exec VBA loader, indicating malicious intent. The Auto_Close macro is present and attempts to write to a file named '1.mstsc' in the public documents directory. This script likely downloads and executes a second-stage payload, leveraging the ShellExecute API.

Heuristics 7

  • 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.
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • Auto_Close macro high OLE_VBA_AUTOCLOSE
    Auto_Close macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • GetObject call high OLE_VBA_GETOBJ
    GetObject call
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
27fdef985c5372a14047b3e2e902c9cedfa0fed1b722d634c9679af441af7d25		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 37124 bytes

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