Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 dca8693c279bbe2b…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:45:24 Authoring application: Microsoft Excel First seen: 2021-09-29
MD5: b4ba8b60734b79c7f8b5b3e9108108f7 SHA-1: a9adc83d3845f1db657ff9acc22bf079b2f40b22 SHA-256: dca8693c279bbe2bac223735480b3e20b269dbcc9657d328f66f9395ee4d1b31
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook containing an Auto_Open function, which is a critical indicator of malicious intent. The presence of dangerous formula APIs in the Auto_Open macro suggests it is designed to execute arbitrary code upon opening. This is a common technique for initial access, often delivered via spearphishing attachments.

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) 6993 bytes
SHA-256: cebc273c36ff5267b7c6a61a00d870cc915b00a493935ae88e51fe8b1583d289
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  sdLdOQORJjO
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C152 
' 0018     27 LABEL : Cell Value, String Constant - BCAHFHRKsMUR len=0 
' 0018     24 LABEL : Cell Value, String Constant - bGbDLUCcO len=0 
' 0018     25 LABEL : Cell Value, String Constant - biazyBFTRY len=0 
' 0018     27 LABEL : Cell Value, String Constant - eFJcjQmyfdUB len=0 
' 0018     27 LABEL : Cell Value, String Constant - eNPkBafKzuxU len=0 
' 0018     25 LABEL : Cell Value, String Constant - eoWtBLXeQs len=0 
' 0018     25 LABEL : Cell Value, String Constant - EvpXoAUUmt len=0 
' 0018     25 LABEL : Cell Value, String Constant - JeLTEhiDch len=0 
' 0018     23 LABEL : Cell Value, String Constant - KBtoVlIO len=0 
' 0018     23 LABEL : Cell Value, String Constant - MKtVgKYG len=0 
' 0018     24 LABEL : Cell Value, String Constant - nJsPzUXYn len=0 
' 0018     24 LABEL : Cell Value, String Constant - pRTSMERGd len=0 
' 0018     23 LABEL : Cell Value, String Constant - PXzYmBnI len=0 
' 0018     26 LABEL : Cell Value, String Constant - QIWJnRvURTE len=0 
' 0018     23 LABEL : Cell Value, String Constant - qjybqbRM len=0 
' 0018     24 LABEL : Cell Value, String Constant - TpLnRwECf len=0 
' 0018     27 LABEL : Cell Value, String Constant - vnGYSWIzAuDi len=0 
' 0018     22 LABEL : Cell Value, String Constant - VRytDEu len=0 
' 0018     25 LABEL : Cell Value, String Constant - yktKEddscd len=0 
' 0018     22 LABEL : Cell Value, String Constant - zwKMDWD 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, Strin
... (truncated)

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