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

Static analysis result for SHA-256 01738fdeb2dd809b…

MALICIOUS

Office (OLE) / .XLS

148.0 KB Created: 2021-02-06 22:23:31 Authoring application: Microsoft Excel
MD5: 46b7ff4279e67cbc59e8fc40442aaa59 SHA-1: 330c34f342bd6f74f954f7cb81fa63f39c58fb1f SHA-256: 01738fdeb2dd809ba3b8804399827ec663e437d402392f9c08d8cec466ebf71e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1204.002 Malicious File

The file contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. The macro uses the EXEC function to run a PowerShell command. This command is constructed using string concatenation and character codes to obscure its true nature, ultimately downloading a file named 'dg.exe' from 'https://cutt.ly/cknGUR2' and executing it. The PowerShell command also attempts to move the downloaded file to the user's AppData directory and execute it from there.

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
39c286c3eb8ee0965084cf277c48794ddd9259e70f5e7dede6dd38636cba2baa
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1237 bytes