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

Static analysis result for SHA-256 031c394fa9cd4361…

MALICIOUS

Office (OLE) / .XLS

139.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: e445762a289ffecb75616573a6710acc SHA-1: 55d31ed14d453429de25e15c0d53fa280a13887c SHA-256: 031c394fa9cd4361106ccd7c353cddbeb40fc02610aa9933bda9861ab63f8fc3
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample is an Excel 4.0 (XLM) macro-enabled spreadsheet. It contains an Auto_Open macro that uses dangerous formula APIs, specifically the RUN function, to execute an external payload. The document body contains a lure instructing the user to enable macros. The macro attempts to download a second-stage payload from the URL zltw15tzezi03nbmru.xyz/w.ttp:// and save it as \zfbfg.eregif.

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
7c9a9bec2dde99680db9c76af504d95b46a4024d082b759a7bf5a4579d7a4229		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 4547 bytes

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