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

Static analysis result for SHA-256 e19c6cc1fe922e62…

MALICIOUS

Office (OLE) / .XLSX

31.0 KB Created: 2021-01-25 16:10:45 Authoring application: Microsoft Excel
MD5: 185c337eeb96808cce0592858a1f7f31 SHA-1: d5d20ae8679b2709a4974a324636b3387d68e0f8 SHA-256: e19c6cc1fe922e62588dbb70a4777d764a84cdef3bdd03c551b0e80fb5b86ec9
160 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic for Applications T1204.002 Malicious File

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. The document body presents a lure, instructing the user to enable editing and content, which is a common technique to bypass security measures. The Auto_Open macro uses dangerous functions, including the RUN function, indicating it likely executes a payload. No specific family could be identified due to the generic nature of the macro and the absence of further indicators.

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.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • 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
93a4ea0a4f61004bb08d60bef2ef58d9db88b4117a408c65187f5bc3ae47a3ac
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3364 bytes