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

Static analysis result for SHA-256 93314fc189908afd…

MALICIOUS

Office (OLE) / .XLS

46.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-09
MD5: 23a5d25d30fc7779b66c70dcef65aa6c SHA-1: de780d58b94f2a662e8942a424f0e8a047b42eb5 SHA-256: 93314fc189908afd8c755786543570b273adb44fa9b1b4082b67885bff8802da
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code. The macros attempt to construct and execute several URLs, including "https://www.zardamarine.com/images/psQbAjrrEOXWPrS/" and "http://labfitouts.com/cgi-bin/Rea3Iu3wGvgAbTset0/". The use of concatenated strings to form URLs suggests an attempt to evade static detection. The primary function of the Auto_Open macro appears to be downloading and executing a second-stage payload from these URLs.

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
f02d63843d495ffd8e99f1b7fe5f87a80501a758c9a61d8585f8be9700f36cb3
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7798 bytes