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

Static analysis result for SHA-256 64f8921376f7e680…

MALICIOUS

Office (OLE) / .XLS

61.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: b66c611239f82ee9b04051591ddedcc9 SHA-1: 57d36b574cd37f069ffa513f533e31e7a12aa79b SHA-256: 64f8921376f7e680cf53e889b99b418b6970a491b32305ce994ef919aef64445
160 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.005 Visual Basic T1218.010 System Binary Proxy Execution: Regsvr32

The sample is an Excel 4.0 (XLM) macro-enabled spreadsheet that uses an Auto_Open macro to execute commands. It impersonates DocuSign to lure the user into enabling macros. The macro attempts to execute 'regsvr32.exe -s C:\LotWin\LotWin2\Horsew.dll', indicating it's designed to download and run a second-stage payload from the specified DLL.

Heuristics 5

  • 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.
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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
  • Document signing service impersonation lure medium SE_DOCUSIGN_LURE
    Document impersonates DocuSign, Adobe Sign, or a similar signing service in a signing-request context

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
4079806a1b1fa296c2735db3069c61e447d1fa3bd6d0b3662d0154f45cf6906e		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2103 bytes

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