Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 89a789b316fd4f2b…

MALICIOUS

Office (OLE)

215.5 KB Created: 2020-08-27 03:27:11 Authoring application: Microsoft Excel First seen: 2020-09-15
MD5: 527f725f8b597b7ab17eceef7966d994 SHA-1: 396414ed81744cd46a2406d80be4f186e349dae9 SHA-256: 89a789b316fd4f2bcd4d4399bdcf671e7dd2156d58ab194ae68c7f0d83f155ee
200 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, including an Auto_Open entry, which is a strong indicator of malicious intent. The macros are designed to execute a PowerShell command that bypasses execution policies and downloads a second-stage payload from a remote source. This is further supported by heuristics indicating suspicious cmd.exe and PowerShell invocations.

Heuristics 5

  • 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.
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • Reference to PowerShell high SC_STR_POWERSHELL
    Reference to PowerShell
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • 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 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1858 bytes
SHA-256: d56faaf7b0247fccc1fd6d054405edce433c858c7ef617976ff8cd21ff9a46fc
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, hidden -  Macro
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0018     27 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x00\x00\x00\x00\x00\x00\x00\x00\xff\x00'
' 0018     73 LABEL : Cell Value, String Constant - cJgK²YLQfnWf9XNyvTnL°TvtKzL°lMTuWBhEXyQYCJ¤µh³Is¤tP3PoHb³N len=0 
' 0018     70 LABEL : Cell Value, String Constant - cw9P¶Ts7p¤c°y¤jbLZI²vkzC0lRNnd8tUQ2Jnml9XNIN3D²uxhaY8rX len=0 
' 0018     56 LABEL : Cell Value, String Constant - EbMcYUMnwA³1q8wpPFYTq8Q5mmCYlJ4rF0k°IGmI9 len=0 
' 0018     23 LABEL : Cell Value, String Constant - ECicbTPC len=0 
' 0018     50 LABEL : Cell Value, String Constant - F8gcf6f²ojqTVZPOqi5kVsI¤4g2tdP¶Frjp len=0 
' 0018     59 LABEL : Cell Value, String Constant - H4efVuvgLz7CcVfxQgfqLHh¤dJMye86Rm4Y²HmRQsµJU len=0 
' 0018     32 LABEL : Cell Value, String Constant - jj1hHcwHRRnqpx77z len=0 
' 0018     33 LABEL : Cell Value, String Constant - la°3pLHGuh2UZoG2At len=0 
' 0018     35 LABEL : Cell Value, String Constant - lWV¤O³¤4hNPL¤39zp2J3 len=0 
' 0018     39 LABEL : Cell Value, String Constant - qB3aAlcO1s°bTPSi89D³aHnM len=0 
' 0018     36 LABEL : Cell Value, String Constant - rCRVM6szIhvFMjNCIiCZ1 len=0 
' 0018     26 LABEL : Cell Value, String Constant - SK9LxPphxlB len=0 
' 0018     28 LABEL : Cell Value, String Constant - T¶Iv4G3ylmsxg len=0 
' 0018     73 LABEL : Cell Value, String Constant - uµ²Xd2kwTxmbBNX7frC²KHHeq³GNm7fCfK8SgNtVdYemN2KlQ°NVg3²FY³ len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' Sheet,Reference,Formula,Value
'  Macro,A1,[],""
'  Macro,A2,RETURN(),""