Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b44489fea4dbe11a…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:17 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: 8a1728d1a58628a75d30451f5e2ea153 SHA-1: e53fc19789515220d6a2fe42e6dff44549a9151e SHA-256: b44489fea4dbe11a03e97588b28ff631ac1ba4d065fead5a0dde2b3aed61fc95
140 Risk Score

Malware Insights

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

The file is an Excel workbook containing Excel 4.0 (XLM) macros. Critical heuristics indicate the presence of an Auto_Open defined name and dangerous formula APIs, suggesting the macro is designed to execute automatically and perform risky actions. The macro sheet is named 'DmBjGsfBCl', and the Auto_Open entry points to a cell that likely contains the malicious code. The truncated document body and lack of explicit script content prevent a more detailed analysis of the 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) 6657 bytes
SHA-256: afaa4215316565d3c7ec5aff4e339ed3ce210b94e333803546cf527a0bb77aa0
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  DmBjGsfBCl
' 0018     21 LABEL : Cell Value, String Constant - aFgYRp len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G188 
' 0018     22 LABEL : Cell Value, String Constant - CibLleG len=0 
' 0018     20 LABEL : Cell Value, String Constant - eKWxf len=0 
' 0018     27 LABEL : Cell Value, String Constant - ewYhnANtjhwI len=0 
' 0018     27 LABEL : Cell Value, String Constant - FFBFFFqQeApR len=0 
' 0018     23 LABEL : Cell Value, String Constant - fNJgfsjn len=0 
' 0018     21 LABEL : Cell Value, String Constant - fVMsuW len=0 
' 0018     22 LABEL : Cell Value, String Constant - ITDReol len=0 
' 0018     23 LABEL : Cell Value, String Constant - kQFBaMKC len=0 
' 0018     20 LABEL : Cell Value, String Constant - kQIVM len=0 
' 0018     26 LABEL : Cell Value, String Constant - lpGJWgiusfl len=0 
' 0018     26 LABEL : Cell Value, String Constant - OmCgNAAuczx len=0 
' 0018     22 LABEL : Cell Value, String Constant - pkAYgQZ len=0 
' 0018     25 LABEL : Cell Value, String Constant - qeqHVfaCcX len=0 
' 0018     20 LABEL : Cell Value, String Constant - SeUYX len=0 
' 0018     24 LABEL : Cell Value, String Constant - ueLGVcHZS len=0 
' 0018     26 LABEL : Cell Value, String Constant - XTlOaNEfKVN len=0 
' 0018     21 LABEL : Cell Value, String Constant - Ygaedw len=0 
' 0018     22 LABEL : Cell Value, String Constant - YwSBtsZ len=0 
' 0018     27 LABEL : Cell Value, String Constant - zNiMrxQrHqeN 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     
... (truncated)

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