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

Static analysis result for SHA-256 1c01354cd22e2e10…

MALICIOUS

Office (OLE) / .XLS

276.0 KB Created: 2020-09-20 21:17:44
MD5: 66ca579b793dc4367aba256fa62f9bf2 SHA-1: deb4047fdd1b203d4202cc716df2d01a35730229 SHA-256: 1c01354cd22e2e101476aeeb6fea291060ff0b536e5761766ba2d7a60facdea6
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1566.001 Spearphishing Attachment T1027 Obfuscated Files or Information

The critical OLE_XLM_DANGEROUS_FN heuristic indicates the presence of dangerous Excel 4.0 macro functions, specifically the RUN function. The extracted macro script reveals an Auto_Open macro that constructs and executes a PowerShell command. This command uses a WebClient object to download a file named 'pd.bat' from the URL 'https://cutt.ly/8jmDPVb' into the environment's temporary directory and then executes it. The script also includes commands to hide and remove the downloaded batch file after execution.

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
7255e9e3d4aa7d986f992766e3e0e0d1db3a5b8df5c4e7549e7d60769f80974f
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1550 bytes