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

Static analysis result for SHA-256 305ff24aefec3e33…

MALICIOUS

Office (OLE) / .XLS

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-27
MD5: 14c612519ff0030463b32a3d7d29d155 SHA-1: b6f5182b5e4b0af4cf9f2eebe5dfbb57d40245b6 SHA-256: 305ff24aefec3e331b80ccde2cf9b027f81e26950fc1dc34421f5d0044b19fc4
140 Risk Score

Malware Insights

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

The critical heuristic OLE_XLM_DANGEROUS_FN indicates the presence of an Excel 4.0 Auto_Open macro that uses the RUN function, which is highly suspicious. The macro sheet contains references to URLs that are likely used to download and execute a second-stage payload. The Auto_Open macro is designed to execute automatically when the workbook is opened.

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
699e21f010c7c5f5713063f52e691ec519f766e81393f8793f7a585cd43d5349		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7635 bytes

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