Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 9ca136785e2e475a…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:50 Authoring application: Microsoft Excel First seen: 2021-10-14
MD5: 82f59dc2e7152bf4b637a335f8b3cbab SHA-1: 1640f6b2ce8ed988493fd7a34841b742e8491549 SHA-256: 9ca136785e2e475a747d63739c293fd1a49390dd859b3933658fb13708d97d88
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 entry, which is a critical finding. This indicates the macro sheet is designed to execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is intended to execute arbitrary code, likely a downloader for a second-stage payload. No specific URLs or hashes were extracted, limiting further IOC identification.

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) 6447 bytes
SHA-256: 022b5dbb0d2c17b357a760dc498e5b7737e2d36bdf9136d0b0acaf54e160796c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  KCosc
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A188 
' 0018     25 LABEL : Cell Value, String Constant - ezZksLRekh len=0 
' 0018     21 LABEL : Cell Value, String Constant - gaCzHE len=0 
' 0018     24 LABEL : Cell Value, String Constant - gQVfwkJDn len=0 
' 0018     22 LABEL : Cell Value, String Constant - IGKMstC len=0 
' 0018     23 LABEL : Cell Value, String Constant - ILKLfMss len=0 
' 0018     24 LABEL : Cell Value, String Constant - MOBdRsffp len=0 
' 0018     26 LABEL : Cell Value, String Constant - MwxMLjSrfSp len=0 
' 0018     20 LABEL : Cell Value, String Constant - NKpMz len=0 
' 0018     23 LABEL : Cell Value, String Constant - NwmbCKqk len=0 
' 0018     22 LABEL : Cell Value, String Constant - OnyvGbD len=0 
' 0018     21 LABEL : Cell Value, String Constant - pCznXM len=0 
' 0018     25 LABEL : Cell Value, String Constant - PeKlQrdKUK len=0 
' 0018     26 LABEL : Cell Value, String Constant - PJGafFyfATC len=0 
' 0018     20 LABEL : Cell Value, String Constant - SIPMO len=0 
' 0018     26 LABEL : Cell Value, String Constant - sMrBsgvOwdn len=0 
' 0018     24 LABEL : Cell Value, String Constant - UBNTVQRwf len=0 
' 0018     25 LABEL : Cell Value, String Constant - uvhdgUyzlq len=0 
' 0018     25 LABEL : Cell Value, String Constant - VguvWSTjXL len=0 
' 0018     25 LABEL : Cell Value, String Constant - vXhQNvEWCh len=0 
' 0018     20 LABEL : Cell Value, String Constant - YnlKa 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 
... (truncated)