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

Static analysis result for SHA-256 ace5d56af2622218…

MALICIOUS

Office (OLE) / .XLS

93.0 KB Created: 2020-05-24 21:15:18 Authoring application: Microsoft Excel
MD5: 491db56cb71d746712081e4fef026c7c SHA-1: 0c90c8720aeed4f1135bda7e8fe9485cabfe837a SHA-256: ace5d56af26222183cf881c6f87989fde2185a5fa709b3ecdc05e39d599d3434
140 Risk Score

Malware Insights

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

The sample is an Excel 4.0 spreadsheet containing an Auto_Open macro, which is a critical indicator of malicious intent. The macro is configured to execute dangerous functions, including 'RUN', suggesting it attempts to download and execute a second-stage payload from the reconstructed URL 'http://gsa.lobcmurizexC\FnMKWkSjyURLONwdTAJEvEDTJMEcGkiQ'. The presence of an Auto_Open entry and the use of risky functions 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
28cfc613ccd73e062d68abf760aed2fd9ebfadcd3498be10249a2f70ae0ed964
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 75752 bytes