Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ca990c9170b77ac3…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:39:00 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: b3fb5d6cdba5e3b64760cc6137622c75 SHA-1: 4884afb95dbcd89652d84a5a007f62a7bb6a5726 SHA-256: ca990c9170b77ac34dfa1404e1105af403f07e2cffe4503bae7884ede297b78b
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 potential execution of arbitrary code. The presence of dangerous formula APIs like RUN further supports this. While the exact payload is not discernible from the provided evidence, the mechanism points to a macro-based execution of 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) 6637 bytes
SHA-256: 3347ebe0c525a5ae308ad2c96b074d3c62df0d418169bc7fa82f5e36246df16e
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 -  edAkCIXzUp
' 0018     26 LABEL : Cell Value, String Constant - AqmDRFBgeuh len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C192 
' 0018     23 LABEL : Cell Value, String Constant - BItErNjb len=0 
' 0018     23 LABEL : Cell Value, String Constant - BNuCghES len=0 
' 0018     21 LABEL : Cell Value, String Constant - DlZfHY len=0 
' 0018     25 LABEL : Cell Value, String Constant - fzOyWseOaB len=0 
' 0018     21 LABEL : Cell Value, String Constant - icLmWk len=0 
' 0018     22 LABEL : Cell Value, String Constant - jasCeyf len=0 
' 0018     22 LABEL : Cell Value, String Constant - LnqaeYc len=0 
' 0018     27 LABEL : Cell Value, String Constant - mXBWZajwngZx len=0 
' 0018     24 LABEL : Cell Value, String Constant - nfjImSXen len=0 
' 0018     25 LABEL : Cell Value, String Constant - NtNQmGflxF len=0 
' 0018     27 LABEL : Cell Value, String Constant - NWdboJLxzwnn len=0 
' 0018     24 LABEL : Cell Value, String Constant - olfXaYtqp len=0 
' 0018     24 LABEL : Cell Value, String Constant - PuLozRThh len=0 
' 0018     20 LABEL : Cell Value, String Constant - RQXds len=0 
' 0018     23 LABEL : Cell Value, String Constant - SYlzFOEL len=0 
' 0018     23 LABEL : Cell Value, String Constant - TktYsbUA len=0 
' 0018     22 LABEL : Cell Value, String Constant - tNoMLJs len=0 
' 0018     27 LABEL : Cell Value, String Constant - UkYlRsXDHqms len=0 
' 0018     23 LABEL : Cell Value, String Constant - zQNeMkQZ 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
' 00
... (truncated)

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