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

Static analysis result for SHA-256 a2c90ca05a6c426a…

MALICIOUS

Office (OLE) / .XLS

177.0 KB Created: 2020-06-02 02:50:28 Authoring application: Microsoft Excel
MD5: 182de316d7c2fee831fae8d32ba43ef9 SHA-1: d22261034e135cd138cc33ca0f36444e0356e366 SHA-256: a2c90ca05a6c426a3573b58ba3170a51510ad5f626adeb1b2a32fc59e2e1dec8
160 Risk Score

Malware Insights

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

The critical OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics indicate the presence of an Excel 4.0 macro sheet with an Auto_Open function that calls risky APIs like RUN. The SE_ENABLE_LURE heuristic suggests the document prompts the user to enable macros. The reconstructed URL from the DOC BODY is likely the download location for a second-stage payload. The macro sheet itself contains numerous BOUNDSHEET and LABEL entries, typical of obfuscated 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
0f943e7bcea1642e33844856e33c395e5610511975a607766a765a21717a3e4e
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 96271 bytes