Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 2993c363521232b2…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:37:11 Authoring application: Microsoft Excel First seen: 2021-10-16
MD5: f073960e9576f990f63008cfcd874be5 SHA-1: 478de0267822751476e2d6e907996d4a05cb9d72 SHA-256: 2993c363521232b2ecd81537f1c260fcbd299a130146957b06b9b521884d964c
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. Heuristics indicate the presence of an Auto_Open function within an XLM macro sheet, which is a known technique for executing malicious code upon opening the workbook. The macro sheet contains numerous obfuscated strings and references to dangerous formula APIs, strongly suggesting it is designed 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) 6562 bytes
SHA-256: 4c1c03b1944659c2fd7ac0f3c110258d6d4bd82a603011f24ad9b3563a056486
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  BVVfSFPZ
' 0018     27 LABEL : Cell Value, String Constant - ApCNkjBXTnDT len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A159 
' 0018     26 LABEL : Cell Value, String Constant - AZcFQKxGrXR len=0 
' 0018     20 LABEL : Cell Value, String Constant - cJofm len=0 
' 0018     27 LABEL : Cell Value, String Constant - EoqDVMoBBIpv len=0 
' 0018     27 LABEL : Cell Value, String Constant - FFOcrgJzdZsX len=0 
' 0018     23 LABEL : Cell Value, String Constant - FHsHsoCn len=0 
' 0018     22 LABEL : Cell Value, String Constant - GxHgFZd len=0 
' 0018     24 LABEL : Cell Value, String Constant - HWHVllAIP len=0 
' 0018     23 LABEL : Cell Value, String Constant - jCxihdro len=0 
' 0018     22 LABEL : Cell Value, String Constant - JYFMKEp len=0 
' 0018     22 LABEL : Cell Value, String Constant - lDZaAWi len=0 
' 0018     22 LABEL : Cell Value, String Constant - LUgryWa len=0 
' 0018     23 LABEL : Cell Value, String Constant - MgCbjdgR len=0 
' 0018     23 LABEL : Cell Value, String Constant - oFpIQagr len=0 
' 0018     23 LABEL : Cell Value, String Constant - QKLIABka len=0 
' 0018     23 LABEL : Cell Value, String Constant - SwUMTkWM len=0 
' 0018     25 LABEL : Cell Value, String Constant - VgEIzvxLlV len=0 
' 0018     24 LABEL : Cell Value, String Constant - xAmCoqglc len=0 
' 0018     24 LABEL : Cell Value, String Constant - YHgQInjQi len=0 
' 0018     26 LABEL : Cell Value, String Constant - yyhJKpnhcXb 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
' 
... (truncated)

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