Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 41fae1de4cf81327…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:41:21 Authoring application: Microsoft Excel First seen: 2021-06-17
MD5: 231c1079afc0bce2977f953f225931b5 SHA-1: 22576a2ef761a903c9b961b7bbd2f000551ff166 SHA-256: 41fae1de4cf813272ffdb9d6f994aac6dcb8cf5ee05c1c0f12892581ce7235fb
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open function, which is a common technique for executing malicious code upon opening. The presence of dangerous formula APIs in the Auto_Open macro suggests an intent to exploit this functionality for malicious purposes, likely to download and execute a secondary payload.

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) 6609 bytes
SHA-256: 4fbfd51fc63287239decede4b6d09926248a4620debadddca9f486ef3596c527
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  IRGL
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G173 
' 0018     21 LABEL : Cell Value, String Constant - EeWhKF len=0 
' 0018     27 LABEL : Cell Value, String Constant - EGjJogOnhdmw len=0 
' 0018     26 LABEL : Cell Value, String Constant - fIkwnEBGTbt len=0 
' 0018     20 LABEL : Cell Value, String Constant - GdlrX len=0 
' 0018     20 LABEL : Cell Value, String Constant - HBWAC len=0 
' 0018     26 LABEL : Cell Value, String Constant - HonjSifGbet len=0 
' 0018     25 LABEL : Cell Value, String Constant - hUSVaQJwMR len=0 
' 0018     24 LABEL : Cell Value, String Constant - IoKuQUKGG len=0 
' 0018     27 LABEL : Cell Value, String Constant - jLRkJolvaWzw len=0 
' 0018     24 LABEL : Cell Value, String Constant - KzmNdtblL len=0 
' 0018     23 LABEL : Cell Value, String Constant - mzJgexEh len=0 
' 0018     23 LABEL : Cell Value, String Constant - ozQGFmBo len=0 
' 0018     26 LABEL : Cell Value, String Constant - PuiMSkQONjY len=0 
' 0018     24 LABEL : Cell Value, String Constant - ShZqVgDWf len=0 
' 0018     22 LABEL : Cell Value, String Constant - WNFAYIB len=0 
' 0018     24 LABEL : Cell Value, String Constant - wVUHXoHnN len=0 
' 0018     27 LABEL : Cell Value, String Constant - WyvURmsnDjjH len=0 
' 0018     20 LABEL : Cell Value, String Constant - xyABz len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZboxGI len=0 
' 0018     20 LABEL : Cell Value, String Constant - ztULD 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     1
... (truncated)

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