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

Static analysis result for SHA-256 c2f4f08af086e410…

MALICIOUS

Office (OLE) / .XLS

36.5 KB Created: 2020-11-27 11:41:25 Authoring application: Microsoft Excel First seen: 2022-02-19
MD5: 8f207030f6cf5ec9d6c9dff2143c7603 SHA-1: e78fe467a0c462aeb9f47421e4e7370040c42e4e SHA-256: c2f4f08af086e410e3bafdb89da4e393adb212caf6ddf37b890d8270320dba2d
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1059.001 PowerShell

The file is an Excel 4.0 macro-enabled spreadsheet. Heuristics indicate the presence of an Auto_Open macro, which is a critical indicator of malicious intent. The macro sheet contains dangerous formula APIs, specifically the RUN function, suggesting it is designed to execute arbitrary commands. The extensive obfuscated text within the document body is likely part of the macro's payload or obfuscation. No specific IOCs like URLs or hashes were extracted, but the presence of the RUN function in an Auto_Open macro strongly suggests a downloader or initial execution vector.

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
cf94c6a999c1a92c68c6922d8bd95136d491ca3197838573229136cd58cc4385
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6694 bytes