Emotet — Office (OLE) / .XLS malware analysis

Static analysis result for SHA-256 8ff5934268d29d7d…

MALICIOUS

Office (OLE) / .XLS

72.0 KB Created: 2022-03-30 21:24:25 Authoring application: Microsoft Excel First seen: 2022-04-04
MD5: 65ebdccd6b316862d08b5defa1958a9f SHA-1: 5973f0c37f112aa7cb1d0df2c3ba65e5ee1cd301 SHA-256: 8ff5934268d29d7dfdf4151accb504b60d0d5a1c9f16d74e6fdae0be7334680d
242 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1218.011 System Binary Proxy Execution: Rundll32 T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical indicator of malicious intent. The macros leverage the `regsvr32.exe` command with a constructed URL, indicating an attempt to download and execute a second-stage payload. The presence of the 'Emotet' ClamAV signature further supports this classification. The macro's execution path involves constructing a URL from concatenated strings, which is a common technique for obfuscation.

Heuristics 6

  • 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.
  • ClamAV: Xls.Downloader.Emotet-b680c97f3ec1c03e-9951030-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-b680c97f3ec1c03e-9951030-0
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://la-csi.com/mt-admin/gCObckGgJyOJWJLZ/
    • https://fffcatfriends.org/adoptables/XN3HjwHemz1AaIw/
    • http://filmmogzivota.rs/js/aHOJNRvJFgK4g/
    • http://https://

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
4c08fe7a6bc71bef4b4f9d9a1e3a86f6e15ab41d083940cde75a4f23b7aab1f8		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7272 bytes

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