Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6d6f8b8a027c634e…

MALICIOUS

Office (OLE)

315.0 KB Created: 2018-07-26 00:26:51 Authoring application: Microsoft Excel
MD5: e14a0a927e2e4f5492df393e7cb9633c SHA-1: 4b28f4018818b7c3352dc72979b7b63fbe5ab0c6 SHA-256: 6d6f8b8a027c634e29a81d8790a7699507b02907583958071397297546d21641
288 Risk Score

Malware Insights

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

The Workbook_Open macro is heavily obfuscated and uses CreateObject to write a script file named "//klPatternGray25.sct" to a path derived from the ALLUSERSPROFILE environment variable. It then uses mshta.exe to execute this script, indicating a downloader or initial execution stage. The use of Wscript.Shell and mshta.exe points to a common pattern for executing malicious scripts.

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
62d9e60b783771164913e455a9c3656ca3db60a7e010dc8dfbc285dd469e274e		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1168 bytes

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