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

Static analysis result for SHA-256 889bab5e6aaa92ed…

MALICIOUS

Office (OLE) / .XLS

167.0 KB Created: 2013-12-10 21:14:00 Authoring application: Microsoft Excel
MD5: e513755516ff49266156904b938906b1 SHA-1: dcdcf29350b50bb0a83d878039872b0ee7f2851a SHA-256: 889bab5e6aaa92ed20c6a57252fc5e917cac1e1e49c4403e76db89671fe540e8
140 Risk Score

Malware Insights

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

The sample is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro and the use of dangerous formula APIs, specifically the RUN function. This suggests the macro is designed to execute arbitrary commands upon opening. While no specific URLs or hashes were extracted, the presence of the RUN function in an Auto_Open macro strongly implies a downloader or initial execution stage for a malicious payload.

Heuristics 3

  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
9b5c6a7d84a1d1743ab07fbedda2c65dac34982e54cc288bee7e45a101f4fcf2
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 81304 bytes