Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 97dc801e1a4761bf…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:46:46 Authoring application: Microsoft Excel First seen: 2021-11-03
MD5: 28ec16d4dd1980f91daf13ef27ef3efa SHA-1: 8fde90682285ddf985b0ed5733d0a882d9f8c95e SHA-256: 97dc801e1a4761bfb968771baf13f304ef2957c8de789d00df961ac162ddbac6
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code within spreadsheets. The presence of dangerous formula APIs like RUN further indicates malicious intent. The macro sheet itself contains obfuscated strings and data, suggesting it's designed to conceal its true purpose, 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) 6471 bytes
SHA-256: f54d88eb8fc352deabd7e06ca5921d14b4b731c85ff757b22b1de8abe4d392ed
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  SPZsC
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H185 
' 0018     26 LABEL : Cell Value, String Constant - bfGsSBEgHQy len=0 
' 0018     27 LABEL : Cell Value, String Constant - bsrKPYtjBXMR len=0 
' 0018     25 LABEL : Cell Value, String Constant - cacMsmHOWP len=0 
' 0018     21 LABEL : Cell Value, String Constant - DsfUEh len=0 
' 0018     22 LABEL : Cell Value, String Constant - dYQRGkc len=0 
' 0018     25 LABEL : Cell Value, String Constant - EDgtqwflKi len=0 
' 0018     23 LABEL : Cell Value, String Constant - eUhVQHvw len=0 
' 0018     24 LABEL : Cell Value, String Constant - hQHNPHWbV len=0 
' 0018     27 LABEL : Cell Value, String Constant - hUgqRRJhfIao len=0 
' 0018     25 LABEL : Cell Value, String Constant - lqgGYPHrxs len=0 
' 0018     24 LABEL : Cell Value, String Constant - MfLaGyJZl len=0 
' 0018     22 LABEL : Cell Value, String Constant - NqYYWTV len=0 
' 0018     26 LABEL : Cell Value, String Constant - pWrziHHJWJd len=0 
' 0018     25 LABEL : Cell Value, String Constant - QuuQxQggLB len=0 
' 0018     27 LABEL : Cell Value, String Constant - qZuzpErqXQLD len=0 
' 0018     22 LABEL : Cell Value, String Constant - SyDGwWU len=0 
' 0018     21 LABEL : Cell Value, String Constant - tItUdd len=0 
' 0018     24 LABEL : Cell Value, String Constant - TVuIIhxqM len=0 
' 0018     21 LABEL : Cell Value, String Constant - UDnCUy len=0 
' 0018     22 LABEL : Cell Value, String Constant - xBWUjQb 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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