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

Static analysis result for SHA-256 923443ed01f1df03…

MALICIOUS

Office (OLE) / .XLS

46.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-09
MD5: d82c6b7154944b291bf1789ee79a7017 SHA-1: b84570d470cab949c47627afda3640ce1b2a36f8 SHA-256: 923443ed01f1df034c684d3162167b1bc113a4632e43143856a770f04c0c1038
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Service Execution T1059.001 PowerShell: PowerShell T1204.002 Malicious File: User Execution: Malicious File

The file is an Excel spreadsheet containing Excel 4.0 macros, specifically an Auto_Open function. This function is designed to execute dangerous formula APIs, including RUN, which is indicative of downloading and executing a second-stage payload. The macro sheet contains multiple URLs that are likely sources for this payload. The presence of the Auto_Open function and the use of RUN indicate a downloader pattern.

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