Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 da22835776127f64…

MALICIOUS

Office (OLE) / .XLSX

145.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel
MD5: 1e22b8c7ffe9db32dc44bc01e7082257 SHA-1: 44d3eb60a329ca8e2d5dda7b1276fc5e13517db9 SHA-256: da22835776127f642b45068f4e374a2ef1ed4a8bc01b4f05b45e3794236d2a36
262 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a known technique for executing malicious code. The macros reconstruct and attempt to download payloads from five distinct URLs. The ClamAV detection and the nature of the embedded URLs strongly suggest this is an Emotet downloader variant. The reconstructed string 'h"&"ttp"&"s:/' indicates the macro's intent to form URLs for payload retrieval.

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.
  • URL reconstructed from XLM cell array (5 URLs) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime) or across individual numeric cells (one ASCII charcode per cell). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries plus LABELSST/RK/NUMBER cells.
  • ClamAV: Doc.Downloader.EmotetRed02222-9938635-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02222-9938635-0
  • 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 https://torostripinginc.com/old/V6BBS9ai/
    • https://geologyadventures.com/error/vEsebODbHUw/
    • https://dev.woodiewin.com/wp-admin/Humbse55L82p72PIbbA/
    • https://xxden.online/wp-content/ge6YV52pidqe/
    • https://firebirdtaclub.com/_borders/TMFaFAVVxivebh/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
1574ee13450fd34682012e2ebea7c020d326605272204fb688e7873d4a7c8165
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6756 bytes