Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 fe3b698262c7a8b1…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:35:15 Authoring application: Microsoft Excel First seen: 2021-10-12
MD5: 509983234669b1eb7ae27a61b5919ca2 SHA-1: 651f1fca76dc8a3a0da4a1001011296585a9f046 SHA-256: fe3b698262c7a8b146ff74a9f150470e21ac68191a3134eb46e00284e01efd66
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, specifically an Auto_Open function. This function is designed to execute automatically when the workbook is opened. The presence of dangerous formula APIs in the Auto_Open macro indicates an intent to run arbitrary code, which is commonly used to download and execute further malicious content. No specific IOCs were extracted, but the technique itself is highly indicative of a downloader or initial execution stage.

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) 6427 bytes
SHA-256: 17327484f0e00284a397869da5fe06ff98710c806172f42d967896bdc8dc2ccd
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ykP
' 0018     22 LABEL : Cell Value, String Constant - AhUOcqN len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D179 
' 0018     20 LABEL : Cell Value, String Constant - DEhZh len=0 
' 0018     21 LABEL : Cell Value, String Constant - DHXmrl len=0 
' 0018     20 LABEL : Cell Value, String Constant - EhyQI len=0 
' 0018     20 LABEL : Cell Value, String Constant - ekPrd len=0 
' 0018     27 LABEL : Cell Value, String Constant - eXdZwKHPpUsR len=0 
' 0018     25 LABEL : Cell Value, String Constant - HWrWQWpHtf len=0 
' 0018     25 LABEL : Cell Value, String Constant - iBiMZgQMsI len=0 
' 0018     22 LABEL : Cell Value, String Constant - NsyyjJs len=0 
' 0018     23 LABEL : Cell Value, String Constant - QcmAomki len=0 
' 0018     22 LABEL : Cell Value, String Constant - rutQgED len=0 
' 0018     24 LABEL : Cell Value, String Constant - rZLJMwCrJ len=0 
' 0018     26 LABEL : Cell Value, String Constant - TUZeXovogue len=0 
' 0018     22 LABEL : Cell Value, String Constant - TwYckjb len=0 
' 0018     26 LABEL : Cell Value, String Constant - ubofAhEQgBY len=0 
' 0018     22 LABEL : Cell Value, String Constant - vImdufI len=0 
' 0018     23 LABEL : Cell Value, String Constant - xcjULYvJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - xvUWuqXfb len=0 
' 0018     24 LABEL : Cell Value, String Constant - yGLdywtKG len=0 
' 0018     21 LABEL : Cell Value, String Constant - YlCnDZ 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     10 LABELSST :
... (truncated)

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