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

Static analysis result for SHA-256 dab7a452faff0adb…

MALICIOUS

Office (OLE) / .XLS

70.5 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-05-30
MD5: 0c42f89c0efc375f27b578fea804cf81 SHA-1: 67c4896fa1fc32f9ae33bb54b276c8b3981b35ac SHA-256: dab7a452faff0adb90589d07b8bd8d80f690364bdbf07123253973c43b74fecc
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. This macro is designed to execute dangerous formula APIs, including the RUN function, which is highly indicative of a downloader. The script attempts to download and execute a second-stage payload from several provided URLs. The presence of the Auto_Open function and the use of the RUN API strongly suggest this is a malicious macro-based document.

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