Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3b1ace9057a879e5…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:44:36 Authoring application: Microsoft Excel
MD5: bb2d96f68d4214a75861680a26acc8d5 SHA-1: 3de68279fce06b6effa1389c82991f98b6fe27f8 SHA-256: 3b1ace9057a879e567d2b28962e4d86f5e7a1574d112a1d9a51f05ad21916cdf
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding. This indicates the macro will execute automatically upon opening the workbook. The presence of dangerous formula APIs in the Auto_Open macro suggests it is designed to perform malicious actions, such as downloading and executing a second-stage payload. No specific IOCs were extracted, but the technique is clear.

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
7d53a694d5c048d9a68d2d5b42b555385230ee3f3da9e4917358126ffdbe4716
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6705 bytes