Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 af931881445f375b…

MALICIOUS

Office (OLE)

660.0 KB Created: 2018-07-26 00:26:51 Authoring application: Microsoft Excel
MD5: 4ccde33da5102adc2990f49331e84b56 SHA-1: e7332faff1e87f6e0a939472b729b4fa23b08df1 SHA-256: af931881445f375b740f42f182c797e8267c576e36f3093b10a935744154df60
256 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059 Command and Scripting Interpreter

The sample is an Excel document containing a remittance advice lure. The Workbook_Open macro is obfuscated and uses CreateObject to write a file to disk and then execute it using Wscript.Shell. The script reconstructs the value "HKCU\Software\Microsoft\Windows\CurrentVersion\Run\IAccessible2Proxy" which is used to establish persistence.

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
  • 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)
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
96cfb2ef6b1d2538beba38c4e39c259d3eacb934abdd2ea13d3cb8a50457fde3		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1211 bytes

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