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

Static analysis result for SHA-256 f409d5bf0243e265…

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-07
MD5: 2d90696cd5be7d242edb0a82b33d4b94 SHA-1: 01694cfab939bbf1e86bba6958e11fbb9bc58bf1 SHA-256: f409d5bf0243e26545b73dec63552af42f941aa1734cbac9db0ec5b2fa37ac23
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1204.002 Malicious File: Malicious File

The file contains critical Excel 4.0 (XLM) macros, including an Auto_Open entry that executes dangerous formula APIs like RUN. The macros attempt to reconstruct and execute several URLs by concatenating string fragments. These reconstructed URLs are: 'https://vibesapparels.com/dQa/Qzuqq5TZO/', 'https://trencasacademiacom/wp-includes/dR7V80Fe/', 'https://chobemastercom/componentes/Gxcs/', and 'http://www.aseguradosaladia.com/wp-content/VH6bhddBGlemnm16b4h/'. This behavior strongly suggests the macro is designed to download and execute a secondary malicious payload.

Heuristics 3

  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
5111faade6798439ce43161a25c95a0c795073df8f05008e90c40cef2fd124d6		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7798 bytes

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