Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 20bad8388c717cf5…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:46:45 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 37901ca6f2b927baa9ffdb1efb1a84f9 SHA-1: 9795cf7c39009f0a5aa6307a9748b0c8875958be SHA-256: 20bad8388c717cf55f477c176191adfb5dc775d712a0d0c9c377457c68cf78ef
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 function, which is a known method for executing malicious code upon opening the workbook. The presence of dangerous formula APIs in the Auto_Open macro suggests an intent to run arbitrary commands. The macro sheet is named 'RZun', which is included as an IOC.

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) 6393 bytes
SHA-256: 6ed6964b38de103a9cbddb5f16de075c1099f6b29e969a58c153bec7100dc00f
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  RZun
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H183 
' 0018     27 LABEL : Cell Value, String Constant - BfLZLWHKfApL len=0 
' 0018     22 LABEL : Cell Value, String Constant - bVQmZCi len=0 
' 0018     23 LABEL : Cell Value, String Constant - DSaICNMf len=0 
' 0018     20 LABEL : Cell Value, String Constant - EzKvJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - GnnTUN len=0 
' 0018     23 LABEL : Cell Value, String Constant - GYPpGVte len=0 
' 0018     26 LABEL : Cell Value, String Constant - HSaGUbLWVVV len=0 
' 0018     21 LABEL : Cell Value, String Constant - izbasJ len=0 
' 0018     25 LABEL : Cell Value, String Constant - rqlNoqYkho len=0 
' 0018     27 LABEL : Cell Value, String Constant - SWCfWfHkkPrt len=0 
' 0018     20 LABEL : Cell Value, String Constant - twlhk len=0 
' 0018     25 LABEL : Cell Value, String Constant - uqvgHZxPaf len=0 
' 0018     23 LABEL : Cell Value, String Constant - URSkburO len=0 
' 0018     22 LABEL : Cell Value, String Constant - vrVetjr len=0 
' 0018     21 LABEL : Cell Value, String Constant - XakPqO len=0 
' 0018     24 LABEL : Cell Value, String Constant - xMCmQjrPl len=0 
' 0018     27 LABEL : Cell Value, String Constant - YeXgYydMNxMd len=0 
' 0018     26 LABEL : Cell Value, String Constant - yLqaydzWOMa len=0 
' 0018     21 LABEL : Cell Value, String Constant - zhyiLo len=0 
' 0018     21 LABEL : Cell Value, String Constant - zvSvSH 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 LAB
... (truncated)

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