Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8476d4d138def121…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:44:35 Authoring application: Microsoft Excel First seen: 2021-06-04
MD5: 4a8cf515ea47a2523ce9f71f6fad0638 SHA-1: f0dfbfe9c9bc1a247c48a0263b0d3852a8a02b5a SHA-256: 8476d4d138def12154ea14ede0228a078d2d4a7e0bd23971b0d3e440d2963317
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Heuristics indicate the presence of an Auto_Open macro, which is a common technique for executing malicious code upon opening the document. The macro uses dangerous formula APIs, specifically the RUN function, to execute arbitrary commands. This strongly suggests the intent is to download and execute a second-stage 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) 6500 bytes
SHA-256: d146038a60b879674ee99bc127300d7e4900cbe396fdd5a79a0927b36daa4c1d
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  sjXsJoq
' 0018     22 LABEL : Cell Value, String Constant - aNGjBCg len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A146 
' 0018     25 LABEL : Cell Value, String Constant - butNeaIUGv len=0 
' 0018     27 LABEL : Cell Value, String Constant - CIWkEPyprYLL len=0 
' 0018     21 LABEL : Cell Value, String Constant - dRpuzU len=0 
' 0018     25 LABEL : Cell Value, String Constant - gbgvlKymvW len=0 
' 0018     20 LABEL : Cell Value, String Constant - gcpTY len=0 
' 0018     23 LABEL : Cell Value, String Constant - gzzrbMTp len=0 
' 0018     23 LABEL : Cell Value, String Constant - IBNqUyQa len=0 
' 0018     23 LABEL : Cell Value, String Constant - ibXlMnlV len=0 
' 0018     26 LABEL : Cell Value, String Constant - JBTbevWniAs len=0 
' 0018     26 LABEL : Cell Value, String Constant - KjOTdTteiJK len=0 
' 0018     22 LABEL : Cell Value, String Constant - kobOoek len=0 
' 0018     26 LABEL : Cell Value, String Constant - LHhmiOUaWAx len=0 
' 0018     23 LABEL : Cell Value, String Constant - LjsXkDxb len=0 
' 0018     21 LABEL : Cell Value, String Constant - LTlAtt len=0 
' 0018     20 LABEL : Cell Value, String Constant - okQUN len=0 
' 0018     23 LABEL : Cell Value, String Constant - PrDLlLjz len=0 
' 0018     21 LABEL : Cell Value, String Constant - rlWwdg len=0 
' 0018     24 LABEL : Cell Value, String Constant - tgfmWYamI len=0 
' 0018     24 LABEL : Cell Value, String Constant - TyWApdKlN 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 
... (truncated)

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