Xls.Dropper.Agent-8130636-0 — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 128ed58bb6f0f83e…

MALICIOUS

Office (OLE) / .XLS

113.0 KB Created: 2020-06-18 23:42:20 Authoring application: Microsoft Excel
MD5: 18bc0a24938fbe7f62c594f63176c14b SHA-1: f32cbf39bb1d66429b9e028396da06f60eae909d SHA-256: 128ed58bb6f0f83eeea8657f7a87b1aba70166be2f47279f2d975b436790c349
260 Risk Score

Malware Insights

Xls.Dropper.Agent-8130636-0 · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

This Microsoft Excel file contains a Workbook_Open VBA macro that is heavily obfuscated. The macro utilizes a custom decoder and CreateObject to execute a payload, as indicated by the 'Obfuscated auto-exec VBA loader' and 'VBA p-code auto-exec with execution tokens' heuristics. The ClamAV detection name 'Xls.Dropper.Agent-8130636-0' further supports its classification as a dropper.

Heuristics 6

  • 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: Xls.Dropper.Agent-8130636-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-8130636-0
  • 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
0758c6a101f0bccbdc73b7ba95aeb5c1b23d8e993de8c9558d2e7edc4758af4c		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 2086 bytes

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