Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 5bf930a1a9102e1b…

MALICIOUS

Office (OLE)

143.0 KB Created: 2018-12-19 10:42:12 Authoring application: Microsoft Excel First seen: 2021-04-10
MD5: b14cd00eb1bfb854005b5bec1e7d6874 SHA-1: f13dbadacce215d0d14862c1257c1abf29242b99 SHA-256: 5bf930a1a9102e1b9687f803cf31f6eaca5dc752deab2b2648d49fb2e90abe8b
202 Risk Score

Heuristics 5

  • 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.
  • URL reconstructed from XLM cell array (1 URL) critical OLE_XLM_CELL_ARRAY_URL
    Excel 4.0 macro sheet stages its payload URL across the BIFF8 Shared String Table (one quoted-char SST entry concatenated with & at runtime), across individual numeric cells (one ASCII charcode per cell), or split across multi-char fragment cells a download formula concatenates by reference (=A1&A2&… / CONCATENATE(...)). The reconstructed URL is invisible to literal-bytes URL extraction because it is never contiguous in the workbook stream. URLs were recovered by walking the BIFF8 record stream and decoding SST entries, LABELSST/RK/NUMBER cells, and FORMULA cell-reference concatenation in token order.
  • 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.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://92.38.135.204/lib2 Referenced by macro
    • http://ns.adobe.com/xap/1.0/Referenced by macro
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#Referenced by macro
    • http://ns.adobe.com/photoshop/1.0/Referenced by macro
    • http://purl.org/dc/elements/1.1/Referenced by macro
    • http://ns.adobe.com/xap/1.0/mm/Referenced by macro
    • http://ns.adobe.com/xap/1.0/sType/ResourceEvent#Referenced by macro
    • http://ns.adobe.com/xap/1.0/sType/ResourceRef#Referenced by macro

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) 1094 bytes
SHA-256: e7fe072239befa666d98cc2cd3cf6d22c1b3a152c971bed150aa4e1ae57d3532
Preview script
First 1,000 lines of the extracted script
' 0085      9 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, hidden -  
' 0085      9 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  
' 0018     28 LABEL : Cell Value, String Constant - Macro1 len=7 ptgRef3d  !A4 
' 0018     28 LABEL : Cell Value, String Constant - Macro2 len=7 ptgRef3d  !A12 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  !A1 
' 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
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' Sheet,Reference,Formula,Value
'  ,A1,Macro1(),""
'  ,A3,HALT(),""
'  ,A5,Macro2(),""
'  ,A8,RETURN(),""
'  ,A14,EXEC( !A30),""
'  ,A17,RETURN(),""
'  ,A30,"CONCATENATE(A31,A32,F31,A33,A34)",""
'  ,A35,HALT(),""

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