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

Static analysis result for SHA-256 4573cc183ae3e77b…

MALICIOUS

Office (OLE) / .XLS

74.0 KB Created: 2020-05-26 20:41:43 Authoring application: Microsoft Excel
MD5: 3d9d2e60fcff5707d3b4e3ac305f2498 SHA-1: 6a4415a3f218900a22166ae5011ec7a822a9c704 SHA-256: 4573cc183ae3e77b9f0ca80b08cdfab015b559ffaa4cded2bfb7a6fe05fb527f
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro that utilizes dangerous functions, specifically RUN. The macro sheet contains obfuscated strings that, when reconstructed, form a URL. This URL is likely used to download and execute a second-stage payload, as indicated by the ClamAV detection signature.

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.
  • ClamAV: Xls.Dropper.Agent-7914573-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Dropper.Agent-7914573-0
  • 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
db70a6a76ff0b51bbaa10c8291d4c583950b6311110cb52d192bdd5b3cdc07d7
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 47254 bytes