Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ac3cc428096079fe…

MALICIOUS

Office (OLE)

316.0 KB Created: 2018-07-26 00:26:51 Authoring application: Microsoft Excel
MD5: 8939f905920f2c23d01ae9dfd3ac653a SHA-1: 335533861fce1313371a79e8ff142dca7be77981 SHA-256: ac3cc428096079fe4572b77a4382eb28b48f7d30279adce3ba69a51f42fe1bd4
288 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The Workbook_Open macro is obfuscated and uses CreateObject to write a script to disk and then execute it via mshta.exe. The script itself is constructed from concatenated strings and environmental variables, making it difficult to fully reconstruct without dynamic analysis. The presence of Wscript.Shell and mshta.exe references strongly suggests the execution of a second-stage payload.

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.
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • Reference to mshta.exe high SC_STR_MSHTA
    Reference to mshta.exe
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject 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
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
c62729403af557b5bcbe7ed756f4aad6536e7333171fedb87225eb03ada48d36		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1157 bytes

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