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

Static analysis result for SHA-256 f1bb4550ec292e23…

MALICIOUS

Office (OLE) / .XLS

180.5 KB Created: 2006-09-16 00:00:00 Authoring application: Microsoft Excel
MD5: 77359a57481249d10aa42679bb3515a3 SHA-1: 7dd8b1bffc986be36afd90ec45b68242e3f19548 SHA-256: f1bb4550ec292e23d06f5f9b9c4a56ac72707606b7aecc413f5bb1e56b7d8ccf
160 Risk Score

Malware Insights

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

The sample contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code upon opening the document. The heuristics indicate the use of dangerous API calls within the macro, including the 'RUN' function. The document body lists several URLs that are likely used to download and execute a second-stage payload. The presence of the Auto_Open macro and the list of suspicious URLs strongly suggests a downloader attack pattern.

Heuristics 4

  • 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.
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
917baaae0e48794e5eb73ae3d5cf93c43110b97da5df3e45bc2f236b5551c875
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 27158 bytes