Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1ad9aee9ec31e465…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-27 11:39:47 Authoring application: Microsoft Excel First seen: 2021-09-25
MD5: 08d0f5afd783068bb0961be1554b9102 SHA-1: 3f5aac47d1db37a9b258d286511a531298cceb83 SHA-256: 1ad9aee9ec31e4652f309619ae20bbf43134bbde06bc42d0098b41f420a67a65
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. The critical heuristic firings indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it's designed to run arbitrary commands. No specific family could be identified, but the technique is commonly used by various malware droppers.

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) 6802 bytes
SHA-256: 4159b712b087638b0cd24b5f02d34b8c421ee61c0ba4b7e263e313b20336cb21
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  llXacJadb
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B173 
' 0018     27 LABEL : Cell Value, String Constant - BHggdAruKZKv len=0 
' 0018     25 LABEL : Cell Value, String Constant - CuGfUObAfG len=0 
' 0018     24 LABEL : Cell Value, String Constant - EccVOHUbR len=0 
' 0018     21 LABEL : Cell Value, String Constant - GjvRCt len=0 
' 0018     20 LABEL : Cell Value, String Constant - heCdU len=0 
' 0018     23 LABEL : Cell Value, String Constant - IDoHlDok len=0 
' 0018     21 LABEL : Cell Value, String Constant - inkVPE len=0 
' 0018     22 LABEL : Cell Value, String Constant - JHcWnQp len=0 
' 0018     27 LABEL : Cell Value, String Constant - KjyQXeGetiLM len=0 
' 0018     23 LABEL : Cell Value, String Constant - NcecURaV len=0 
' 0018     20 LABEL : Cell Value, String Constant - OUdJm len=0 
' 0018     25 LABEL : Cell Value, String Constant - oYtYIMJmQZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - pKzpA len=0 
' 0018     27 LABEL : Cell Value, String Constant - QpPqdeyLfQph len=0 
' 0018     24 LABEL : Cell Value, String Constant - tMIDigTxb len=0 
' 0018     24 LABEL : Cell Value, String Constant - UdLqcchPi len=0 
' 0018     25 LABEL : Cell Value, String Constant - UpUboMfXha len=0 
' 0018     23 LABEL : Cell Value, String Constant - WorzzCWL len=0 
' 0018     22 LABEL : Cell Value, String Constant - XkXMrJZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - YUVsYccQ 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     
... (truncated)

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