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

Static analysis result for SHA-256 37b83df54a5ec73a…

MALICIOUS

Office (OLE) / .XLS

227.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 43103cdbf932ed8837ba8189ffe63f41 SHA-1: 3ec49861a177e504fd484603eee8a2b2b19dab74 SHA-256: 37b83df54a5ec73a6c33d5861f6e66ea7dc71699ae51e2d2355c80cf43b20504
180 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that uses dangerous functions like RUN, and includes environment evasion checks. The document body presents a fake protection message, instructing the user to enable editing and content, which is a common lure for macro-based malware. The Auto_Open macro likely executes a secondary payload.

Heuristics 4

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • XLM Auto_Open environment-evasion HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
9dd85d2f1a5e4b1bd28ce667377c59a2ca6fd60cb412780d7e8b5b61427a464f		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 329652 bytes

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