Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 d141bc335e621dca…

MALICIOUS

Office (OLE)

143.0 KB Created: 2016-10-07 21:26:00 Authoring application: Microsoft Excel First seen: 2020-07-24
MD5: ed1d2c8d4986bff5a0fb1d4e0992ff33 SHA-1: a63f84b1049b338816d4a1d5c8479ff9c05364f3 SHA-256: d141bc335e621dca9cd1e3340be2987f8d6b057fe384450c4b1059c1cc98ab0d
80 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristic firing indicates the presence of an Excel 4.0 macro sheet with an Auto_Open entry, which is a common technique for executing malicious code upon opening the document. The macro sheet itself is heavily obfuscated and truncated, preventing a detailed analysis of its specific actions, but the Auto_Open entry strongly suggests it's designed to download and execute a secondary payload. The presence of this macro sheet points to a spearphishing attachment delivery method.

Heuristics 2

  • 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.
  • 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) 93143 bytes
SHA-256: d313c67d46d05b7487b7457bcbb34b1ba0a2c92dfe928dba2ef1e4d585c35184
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  QLM9LO
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgRef3d  Sheet!FY59293 
' 0018     32 LABEL : Cell Value, String Constant -            hidden len=7 ptgRef3d  Sheet!FY59299 
' 0018     31 LABEL : Cell Value, String Constant -       hidden len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x00\x00 \xe7\x80\xe7\x83\x00\x83\x00'
' 0018     28 LABEL : Cell Value, String Constant -        hidden len=7 ptgRef3d  Sheet!FY59295 
' 0018     29 LABEL : Cell Value, String Constant -     hidden len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x00\x00\x01\xe7\x88\xe7\xaf\x00\xaf\x00'
' 0018     29 LABEL : Cell Value, String Constant -     hidden len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x00\x00\x7f\xe7$\xe8\x9c\x00\x9c\x00'
' 0018     28 LABEL : Cell Value, String Constant - MsvMeZ hidden len=7 ptgRef3d  Sheet!FY59293 
' 0018     32 LABEL : Cell Value, String Constant -            hidden len=7 ptgRef3d  Sheet!FY59297 
' 0018     30 LABEL : Cell Value, String Constant -      hidden len=11 ptgArea3d  *INCOMPLETE FORMULA PARSING* Remaining, unparsed expression: b'\x00\x00:\xe7\x8b\xe7\x85\x00\x85\x00'
' 0018     32 LABEL : Cell Value, String Constant -            hidden len=7 ptgRef3d  Sheet!FY59298 
' 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 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABEL
... (truncated)

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