Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 6bd9cbd818d5ed7b…

MALICIOUS

Office (OLE) / .XLSX

129.5 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 4a909758b2ef994d1a95035fff6af33e SHA-1: 0371fce34f21a7ec2bed84e96186cc7c6a0837db SHA-256: 6bd9cbd818d5ed7b770c91f4a07b0a15cb72b9ace02a044ddf046c8b68e15014
300 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1140 Deobfuscate or Reverse Engineer

The sample contains an obfuscated VBA macro that utilizes `CreateObject` to instantiate `Wscript.Shell`. This script is designed to execute a batch file and a VBScript payload, which are dropped to `c:\programdata\`. The embedded PowerShell command decodes a list of URLs, likely for downloading additional malicious content. The presence of `Workbook_Open` and `CreateObject` heuristics, along with the obfuscated loader, strongly indicates a downloader functionality.

Heuristics 7

  • 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.
  • ClamAV: Doc.Downloader.EmotetRed02220-9938909-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02220-9938909-0
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
7a075e02dc1e88807280b9b84946715e79a3c091d50391301434649c77b78ea1		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 12808 bytes

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