Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3428a068041dbde5…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:29 Authoring application: Microsoft Excel First seen: 2021-09-27
MD5: 428c92797c4bbc74bc9762e9014ff0a9 SHA-1: 20540a82bf0229d1b07bb4f77abb70b68a6ba567 SHA-256: 3428a068041dbde597c5b6caefeb13c95855164a0d0d7e77f9251b566171c95b
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 sheet containing an Auto_Open function, which is a critical finding indicating automatic execution upon opening. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely downloading and running a second-stage payload. The obfuscated document body content does not provide further clues to the specific lure.

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) 6628 bytes
SHA-256: 0a3029385201762245e47b45c62f148891f0427f1162cf7d22a6a366b2847c69
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  cDhURrBiLD
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B198 
' 0018     24 LABEL : Cell Value, String Constant - BGmwIoUWq len=0 
' 0018     26 LABEL : Cell Value, String Constant - cNTkZokjOsV len=0 
' 0018     27 LABEL : Cell Value, String Constant - cOhSemsbvuWf len=0 
' 0018     22 LABEL : Cell Value, String Constant - DavkMda len=0 
' 0018     25 LABEL : Cell Value, String Constant - dWeeajajLO len=0 
' 0018     27 LABEL : Cell Value, String Constant - HoZLsKLXUaxA len=0 
' 0018     23 LABEL : Cell Value, String Constant - InkRtJVx len=0 
' 0018     24 LABEL : Cell Value, String Constant - jPWvUNaav len=0 
' 0018     24 LABEL : Cell Value, String Constant - KUQImUUlQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - lXPPgG len=0 
' 0018     22 LABEL : Cell Value, String Constant - MNrKGxJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - nfcjzIE len=0 
' 0018     26 LABEL : Cell Value, String Constant - NKxzAoAszyZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - qWywXvzZruc len=0 
' 0018     22 LABEL : Cell Value, String Constant - TBQVyIU len=0 
' 0018     22 LABEL : Cell Value, String Constant - TmFOvat len=0 
' 0018     23 LABEL : Cell Value, String Constant - upDJFqZR len=0 
' 0018     20 LABEL : Cell Value, String Constant - VpTzL len=0 
' 0018     21 LABEL : Cell Value, String Constant - WAklCQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - xAUauGcgJHZ 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
' 0
... (truncated)