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

Static analysis result for SHA-256 81ad6dc2417ff369…

MALICIOUS

Office (OLE) / .XLS

41.0 KB Created: 2015-06-05 18:17:20 Authoring application: Microsoft Excel
MD5: 1c6836f36ef675d04314410332c3fc66 SHA-1: 00457e5f685e7c4b241ff24471c175cf1bcb4b4e SHA-256: 81ad6dc2417ff36910a469b9bc1c058a66248ca8847247c33674735775d75282
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry point, which is a known method for executing malicious code. The presence of a dangerous formula API in the Auto_Open macro suggests it is designed to perform actions beyond typical spreadsheet functions, such as downloading and executing a payload. No specific family could be identified from the available evidence.

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
afc384f2d5b8dd12fd99c34fd2af58499f707031cad72157ac2cb88884c688b5
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7792 bytes