Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 aaf6e7e34be687b8…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:46:44 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: 6823d244b0fe448bdfeba4c23b03980f SHA-1: 380f8b67a0d6a8b2c149a3f3ca6e115b0763571c SHA-256: aaf6e7e34be687b81939e7bd0b5ac792c0783b76adb89e889c5e06ec59aa5ed4
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding indicating automatic execution upon opening. The heuristics also flag the use of dangerous formula APIs within the XLM macro, suggesting it's designed to execute arbitrary code. This pattern is commonly used to download and execute 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) 6894 bytes
SHA-256: 3757390b0d66d788d991321488658e681ab73e56e5b3c23dc7a125fb18814b25
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  xsOYArqS
' 0018     26 LABEL : Cell Value, String Constant - AbgZOWUTnRi len=0 
' 0018     27 LABEL : Cell Value, String Constant - AlrgIjFErUoc len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E178 
' 0018     24 LABEL : Cell Value, String Constant - bCBLWwWTC len=0 
' 0018     20 LABEL : Cell Value, String Constant - EAJdo len=0 
' 0018     20 LABEL : Cell Value, String Constant - fJhDh len=0 
' 0018     20 LABEL : Cell Value, String Constant - fuqLC len=0 
' 0018     26 LABEL : Cell Value, String Constant - GwRREFkOapS len=0 
' 0018     24 LABEL : Cell Value, String Constant - jBxMuRmSF len=0 
' 0018     25 LABEL : Cell Value, String Constant - JCtLDLJTqs len=0 
' 0018     20 LABEL : Cell Value, String Constant - kocQj len=0 
' 0018     23 LABEL : Cell Value, String Constant - KXRtyNtN len=0 
' 0018     21 LABEL : Cell Value, String Constant - MIMXgU len=0 
' 0018     27 LABEL : Cell Value, String Constant - nlxUtGDpwuKY len=0 
' 0018     24 LABEL : Cell Value, String Constant - OXCshBykB len=0 
' 0018     26 LABEL : Cell Value, String Constant - QebFSXgDGiq len=0 
' 0018     22 LABEL : Cell Value, String Constant - RaHptYS len=0 
' 0018     26 LABEL : Cell Value, String Constant - TtAUoBywTGB len=0 
' 0018     22 LABEL : Cell Value, String Constant - ucwvIOL len=0 
' 0018     24 LABEL : Cell Value, String Constant - uhiNkNiaN len=0 
' 0018     26 LABEL : Cell Value, String Constant - UrAkqseDRdJ 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
' 00f
... (truncated)

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