Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b378a28bc2699349…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:25:58 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: 7975829e48d6daf2db66bb05c5e0e036 SHA-1: fa021dc91575b7ffbab902458d44559511299b4c SHA-256: b378a28bc2699349d52a88f874764d687c6e47685e276a732edefea198fc4c2a
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 technique for executing malicious code upon opening the document. The critical heuristics indicate the presence of dangerous formula APIs within the macro, suggesting it's designed to download and execute a secondary payload. No specific family could be identified.

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: f4ecb835d7a4c284a76e519bfc64e7c375e081e7496330b081d9fafa7a0aaa0b
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 -  aGmXR
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D195 
' 0018     23 LABEL : Cell Value, String Constant - BesEsFhq len=0 
' 0018     26 LABEL : Cell Value, String Constant - bmVjwgSlThX len=0 
' 0018     27 LABEL : Cell Value, String Constant - fBznNQnpYYka len=0 
' 0018     25 LABEL : Cell Value, String Constant - fyfwMVhizm len=0 
' 0018     21 LABEL : Cell Value, String Constant - IDlZSw len=0 
' 0018     21 LABEL : Cell Value, String Constant - ITBKCA len=0 
' 0018     20 LABEL : Cell Value, String Constant - jCrpQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - kGYrrLl len=0 
' 0018     20 LABEL : Cell Value, String Constant - mghXy len=0 
' 0018     26 LABEL : Cell Value, String Constant - MxOTmtZznsk len=0 
' 0018     24 LABEL : Cell Value, String Constant - MzfHzlAVw len=0 
' 0018     21 LABEL : Cell Value, String Constant - PhHdMB len=0 
' 0018     24 LABEL : Cell Value, String Constant - PSCNmXzES len=0 
' 0018     23 LABEL : Cell Value, String Constant - tPBGaZOo len=0 
' 0018     20 LABEL : Cell Value, String Constant - tXfco len=0 
' 0018     26 LABEL : Cell Value, String Constant - vHCWZqjMOJg len=0 
' 0018     24 LABEL : Cell Value, String Constant - VKOsPfceF len=0 
' 0018     20 LABEL : Cell Value, String Constant - vQnwU len=0 
' 0018     25 LABEL : Cell Value, String Constant - XJCQSyUgJY len=0 
' 0018     21 LABEL : Cell Value, String Constant - YKsmGG 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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