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

Static analysis result for SHA-256 656e8e49a0fd3b0c…

MALICIOUS

Office (OLE) / .XLS

331.0 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 07eb30455b543ae6ac00c12f3262ecde SHA-1: f16273f46e4e309c23f4a31480c56f93da175b0b SHA-256: 656e8e49a0fd3b0cf5fb2048763e6757a8ee8d4365a45d5f9e61c9f650f18773
242 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros with an Auto_Open entry, which is a critical finding indicating automatic execution upon opening. The macros utilize the RUN function and a CALL to 'kernel32.CreateA' with obfuscated arguments, strongly suggesting the execution of a second-stage payload. The embedded URL 'https://chica.media/ds/231120.gif' is likely the source of this payload, aligning with the ClamAV detection of 'Doc.Downloader'.

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: Doc.Downloader.Docusign0521-9864805-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Docusign0521-9864805-0
  • Reference to ShellExecute API high SC_STR_SHELLEXEC
    Reference to ShellExecute API
  • 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://chica.media/ds/231120.gif
    • https://chica.media/ds/231120.gif�

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
f47affe8c13bcf147c60cdfcb7548aa5c789e981f4872a53ebdda3b841e12f12		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6059 bytes

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