Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f4f0127923c4a1c6…

MALICIOUS

Office (OLE)

317.0 KB Created: 2018-07-26 00:26:51 Authoring application: Microsoft Excel
MD5: bd59e42a9ee00ba415448c31190e57d7 SHA-1: 95bc249a25513514f1859b690fdcc41f7fb78bac SHA-256: f4f0127923c4a1c69aab04516907fd4010f9af8302e132b972d053813577b18d
328 Risk Score

Malware Insights

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

The sample contains an obfuscated auto-exec VBA loader within the Workbook_Open macro. This macro utilizes CreateObject to write a script to a file and then executes it using mshta.exe via Wscript.Shell. The script itself appears to be designed to download and execute a second-stage payload, indicated by the use of Wscript.Shell and mshta.exe.

Heuristics 9

  • 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.
  • Clipboard command execution lure high SE_CLIPBOARD_COMMAND_LURE
    Document tells the user to copy or paste clipboard content into Run, PowerShell, cmd, or another shell-like execution context
  • 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
da2e58c16bc78a5c004cdaf9f92b3f6a6dbdd623dc8246c7051736bb2c3fcbf5		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1178 bytes

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