Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c4b5bf90bcde6480…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:35:19 Authoring application: Microsoft Excel First seen: 2021-09-24
MD5: d060adeaef9db2fa49de581a83571982 SHA-1: dcf4221ff30c4cfcf7adbe6862137f88a8608597 SHA-256: c4b5bf90bcde6480e45dc20b86de6d3cbc547edaca0a1bfa1b20aebcd0af1e6e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open entry, which is a known method for executing malicious code. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting an attempt to run arbitrary commands or download further payloads. No specific URLs or executable payloads were directly extracted, hence the family is unknown.

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 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6485 bytes
SHA-256: 6e327ad38788fe39b3a1179ff1e11b423abc1063ac8c4d331e206af61212774c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  FBJqaWv
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I175 
' 0018     21 LABEL : Cell Value, String Constant - bWtnAM len=0 
' 0018     24 LABEL : Cell Value, String Constant - FykLIHlGa len=0 
' 0018     26 LABEL : Cell Value, String Constant - IykJeSBcpED len=0 
' 0018     22 LABEL : Cell Value, String Constant - JINAjFx len=0 
' 0018     20 LABEL : Cell Value, String Constant - KQfxm len=0 
' 0018     20 LABEL : Cell Value, String Constant - LaHMC len=0 
' 0018     23 LABEL : Cell Value, String Constant - LxvLkZIB len=0 
' 0018     22 LABEL : Cell Value, String Constant - NQqhLaD len=0 
' 0018     24 LABEL : Cell Value, String Constant - opgNBvDkO len=0 
' 0018     24 LABEL : Cell Value, String Constant - pqlqrsUjM len=0 
' 0018     25 LABEL : Cell Value, String Constant - ptFHzUzeTq len=0 
' 0018     24 LABEL : Cell Value, String Constant - SnDOLzqcL len=0 
' 0018     22 LABEL : Cell Value, String Constant - tkHWAum len=0 
' 0018     22 LABEL : Cell Value, String Constant - uCriJQK len=0 
' 0018     26 LABEL : Cell Value, String Constant - UKSehczltTI len=0 
' 0018     21 LABEL : Cell Value, String Constant - vfSTXP len=0 
' 0018     25 LABEL : Cell Value, String Constant - WRiJoWYnit len=0 
' 0018     20 LABEL : Cell Value, String Constant - XOwQQ len=0 
' 0018     24 LABEL : Cell Value, String Constant - ZBsYZTVpZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZrhPXSFQtWW len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABE
... (truncated)