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

Static analysis result for SHA-256 cbd5b0454385324b…

MALICIOUS

Office (OLE) / .XLS

67.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-23
MD5: a8777e5596125dadbb7563052324e1bb SHA-1: bbd66379044f8d49541a7ae6d793b44a0aea3b49 SHA-256: cbd5b0454385324baee6fc97124c8656ea55f4272f7365e2fbcf570470cba4e6
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open function, which is a known technique for executing malicious code. The XLM Auto_Open macro uses dangerous formula APIs, specifically the RUN function, to download and execute a payload from one of the provided URLs. The macro sheet contains multiple URLs that are likely used for this purpose.

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
67f6b164c4d6ea1ea8efe2ccdff056dde7fd1072da2bb20afe3b275864086c71		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7678 bytes

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