Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c5ddefa7b629f8b9…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:40:40 Authoring application: Microsoft Excel First seen: 2021-06-04
MD5: d9f2a6cbbbec8d367677beab8a106784 SHA-1: 1709e76a6706b9afedc8e8ee3ca7a9be0b4c9c09 SHA-256: c5ddefa7b629f8b9295b3a0f126337246a7ed9ffc74b7284cd2e90ce0a4071ae
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-enabled workbook. Static analysis identified an Auto_Open defined name and the use of dangerous formula APIs, indicating that the macro sheet is designed to execute code automatically upon opening. The presence of XLM macros and the Auto_Open function strongly suggests the intent to download and execute a secondary payload, a common technique for initial compromise.

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) 6863 bytes
SHA-256: ccd3ede733f553669b2cad58e30a9aa66e48ba803d01e9a6e1fdff0a9ffaec80
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 -  EghYQSrorB
' 0018     27 LABEL : Cell Value, String Constant - ACfswfSvuHfw len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G188 
' 0018     22 LABEL : Cell Value, String Constant - BESsqIN len=0 
' 0018     26 LABEL : Cell Value, String Constant - dXjjKKBKxBr len=0 
' 0018     26 LABEL : Cell Value, String Constant - efWcepYuEeU len=0 
' 0018     23 LABEL : Cell Value, String Constant - IbaWgEwQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - IpwQO len=0 
' 0018     27 LABEL : Cell Value, String Constant - jPEnUfWnUWBz len=0 
' 0018     24 LABEL : Cell Value, String Constant - MDfjmuckI len=0 
' 0018     25 LABEL : Cell Value, String Constant - NcbwJTSNqU len=0 
' 0018     24 LABEL : Cell Value, String Constant - qpJMPkVzL len=0 
' 0018     27 LABEL : Cell Value, String Constant - qYJNfgSoyUnb len=0 
' 0018     24 LABEL : Cell Value, String Constant - RoBnSVpyC len=0 
' 0018     26 LABEL : Cell Value, String Constant - ShDpnPFRIQj len=0 
' 0018     27 LABEL : Cell Value, String Constant - sxprTzvVfztw len=0 
' 0018     23 LABEL : Cell Value, String Constant - tqdOuelj len=0 
' 0018     21 LABEL : Cell Value, String Constant - TWYmcG len=0 
' 0018     21 LABEL : Cell Value, String Constant - UKlkQy len=0 
' 0018     23 LABEL : Cell Value, String Constant - uvCdwAlv len=0 
' 0018     25 LABEL : Cell Value, String Constant - VFcGkvQLUf len=0 
' 0018     20 LABEL : Cell Value, String Constant - vXLJa 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/
... (truncated)

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