Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 df7c986400218dcf…

MALICIOUS

Office (OLE)

222.0 KB Created: 2021-02-06 22:23:31 Authoring application: Microsoft Excel
MD5: 7a5af4e94c392473579a2d8cfddbb913 SHA-1: ff0ecb1a73c24f7658d3792d99f9c90243505960 SHA-256: df7c986400218dcf5ed51d86b09b921916e0b259c1cca21625334b0470298356
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 PowerShell T1204.002 Malicious File

The critical heuristics indicate the presence of Excel 4.0 macros with dangerous functions, specifically an Auto_Open entry. The extracted macro script reveals a complex PowerShell command constructed using character concatenation. This command is designed to download a file named 'vc.exe' from the URL 'https://tinyurl.com/2vwqjf3z', save it to the temporary directory, and then execute it. This indicates a downloader or dropper 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
ea79110e45a92b766f671b7bf7acbfb8b49bad17066157713e6eeea333d474cc
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1236 bytes