Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 278f1244b407f4cf…

MALICIOUS

Office (OLE)

313.5 KB Created: 2018-07-26 00:26:51 Authoring application: Microsoft Excel
MD5: c2d2852e6521b53d220c38d2418fc982 SHA-1: 4ea6c060741d7161cee11c3ccc085790c9378e6f SHA-256: 278f1244b407f4cf155a7e63341681f7f5e61b003e1c2a3a70a9ccfd575006e0
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 a file and then execute it using mshta.exe. The script is constructed from concatenated strings and environment variables, ultimately leading to the execution of a second-stage payload. The use of Wscript.Shell and mshta.exe indicates a likely attempt to download and run further malicious content.

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
ad257c55135fcd0658b9406a522d820ed27de1f6dbe58badc9c3dce3c670b7a9		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1215 bytes

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