Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 f84b6ec8831a67d6…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:45:28 Authoring application: Microsoft Excel First seen: 2021-10-01
MD5: d3f85999e86f658137e6a9f66ed6d9fa SHA-1: 905f9cd2d9d60679f48480b99330efaca1ed6ab7 SHA-256: f84b6ec8831a67d6b7b2c93fd8581d359f9d62ae0c33c72990fb5b6113dade82
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 defined name, which is a critical finding indicating automatic execution upon opening. The heuristics also flag the use of dangerous formula APIs within the XLM macro, suggesting an attempt to execute arbitrary code. While the specific payload is not detailed, the presence of Auto_Open points to a downloader or initial execution vector.

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) 6745 bytes
SHA-256: e9cb1f18e405c305e20c91fd61a5eac745e239917137e98dbded4b966b7ad6fa
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  yYJaLqEP
' 0018     24 LABEL : Cell Value, String Constant - acCnjyZTo len=0 
' 0018     21 LABEL : Cell Value, String Constant - aoEtfc len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E156 
' 0018     27 LABEL : Cell Value, String Constant - CBGwQHnWJSGC len=0 
' 0018     27 LABEL : Cell Value, String Constant - cNINQtrgmQyX len=0 
' 0018     24 LABEL : Cell Value, String Constant - dbNJGwhxN len=0 
' 0018     27 LABEL : Cell Value, String Constant - DxBlOfmzRnbj len=0 
' 0018     25 LABEL : Cell Value, String Constant - IQFXhwJvvd len=0 
' 0018     22 LABEL : Cell Value, String Constant - KHbvTkv len=0 
' 0018     20 LABEL : Cell Value, String Constant - krWen len=0 
' 0018     25 LABEL : Cell Value, String Constant - lVASzCraFf len=0 
' 0018     21 LABEL : Cell Value, String Constant - MKOmuQ len=0 
' 0018     23 LABEL : Cell Value, String Constant - mmekGSnN len=0 
' 0018     24 LABEL : Cell Value, String Constant - NzEkzLWcT len=0 
' 0018     20 LABEL : Cell Value, String Constant - UxyUq len=0 
' 0018     21 LABEL : Cell Value, String Constant - voyqmv len=0 
' 0018     21 LABEL : Cell Value, String Constant - WMokXG len=0 
' 0018     21 LABEL : Cell Value, String Constant - WTRUIG len=0 
' 0018     26 LABEL : Cell Value, String Constant - YTDJUkogNqS len=0 
' 0018     25 LABEL : Cell Value, String Constant - zeGqLkibzA len=0 
' 0018     23 LABEL : Cell Value, String Constant - zGAFjKqK 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     
... (truncated)

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