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

Static analysis result for SHA-256 881918615065ebb5…

MALICIOUS

Office (OLE) / .XLS

71.0 KB Created: 2015-06-05 18:19:34 Authoring application: Microsoft Excel First seen: 2022-06-07
MD5: 40c84383fef5544a15c8bef4d7bcb394 SHA-1: 5ccef9488188657669b02a33b3d99e10628d84f3 SHA-256: 881918615065ebb57b86f80612f7f6e90418fd03d3f53484cbe4dcffa43926cf
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Service Execution: Service Control T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious File: User Execution: Malicious File

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a critical indicator of malicious intent. The macros utilize dangerous formula APIs, including the RUN function, suggesting an attempt to execute arbitrary code. The extracted URLs are likely used to download and execute a second-stage payload. The presence of the Auto_Open macro and the use of the RUN function strongly indicate a downloader or droppper functionality.

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
5111faade6798439ce43161a25c95a0c795073df8f05008e90c40cef2fd124d6
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 7798 bytes