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

Static analysis result for SHA-256 ef002d4d0e85ce74…

MALICIOUS

Office (OLE) / .XLS

36.0 KB Created: 2020-11-27 11:40:05 Authoring application: Microsoft Excel First seen: 2022-04-19
MD5: 91ae6cc46ebce6888f886065a6ef4201 SHA-1: a74ff515649e9dee8d78002dc6eaf95e0b276a1b SHA-256: ef002d4d0e85ce74a057371523873f0908eb2a1b0172ffbe21b6ac90da7797d7
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File

The sample is an Excel 4.0 (XLM) macro-enabled workbook. Critical heuristics indicate the presence of an Auto_Open macro, which is a common technique for automatic execution upon opening. The macro sheet contains a reference to a dangerous function, 'RUN', suggesting it is designed to execute arbitrary commands. While the specific payload is not directly visible, the presence of Auto_Open and the 'RUN' function strongly implies the macro's intent is to download and execute a second-stage 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
ed051b9d22ce624589d1999f221a811c1d8dc6b764008ebd21e781f8aeb795da
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6844 bytes