Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8683b69471ec7531…

MALICIOUS

Office (OLE)

318.5 KB Created: 2018-07-26 00:26:51 Authoring application: Microsoft Excel
MD5: 5d7e91a055573a70c596b58c5c7506d9 SHA-1: fdae3503f37866112dbe969d5bf204924ba0f3e1 SHA-256: 8683b69471ec7531228b1c48d2b362a5c6c9f0fb5e8fb0e3480797caa9a41d58
288 Risk Score

Malware Insights

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

The sample is an Excel file containing an obfuscated Workbook_Open VBA macro. This macro is designed to decode a string, write it to a file named '//klNormalLoad.sct', and then execute it using mshta.exe. This indicates a downloader or dropper functionality, likely leading to 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
1523ec9a5894659722bffc9120a7b8cd6992a022086ebb47118c4921862a8856		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1150 bytes

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