Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 55d4a1d1b57211dc…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:40:44 Authoring application: Microsoft Excel First seen: 2021-09-29
MD5: 48515fbfacb23bdd7dc148eb8dd9d614 SHA-1: fa7bce371b4aec253549c76afeead6f7badf55d0 SHA-256: 55d4a1d1b57211dcf8fef45b7c7561999f3855a0cc909ff9d67100cb43ae67e8
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. This macro is configured to execute dangerous formula APIs, indicating an intent to run arbitrary code. The presence of an Auto_Open macro strongly suggests the file is designed to download and execute a second-stage payload upon opening.

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) 6698 bytes
SHA-256: 835d8253fc0099197e4964c2056f23664ce92c1a0f89b08fc98eaf217ea9263d
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 -  KorSW
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A155 
' 0018     27 LABEL : Cell Value, String Constant - AVfwJHLInZQS len=0 
' 0018     23 LABEL : Cell Value, String Constant - BeBuUoCj len=0 
' 0018     21 LABEL : Cell Value, String Constant - bwhbpE len=0 
' 0018     23 LABEL : Cell Value, String Constant - cmkWYLEi len=0 
' 0018     25 LABEL : Cell Value, String Constant - EngIEhulYk len=0 
' 0018     24 LABEL : Cell Value, String Constant - ERinJMnYv len=0 
' 0018     26 LABEL : Cell Value, String Constant - fQEmPryWLry len=0 
' 0018     26 LABEL : Cell Value, String Constant - GfTXyUghvVU len=0 
' 0018     23 LABEL : Cell Value, String Constant - hTSekhGG len=0 
' 0018     20 LABEL : Cell Value, String Constant - jENlp len=0 
' 0018     21 LABEL : Cell Value, String Constant - JIZTnv len=0 
' 0018     23 LABEL : Cell Value, String Constant - JvLumTYm len=0 
' 0018     25 LABEL : Cell Value, String Constant - jyoQejCwFp len=0 
' 0018     25 LABEL : Cell Value, String Constant - kdspWvCNpB len=0 
' 0018     21 LABEL : Cell Value, String Constant - NkFMOD len=0 
' 0018     24 LABEL : Cell Value, String Constant - OVXoHEnBu len=0 
' 0018     25 LABEL : Cell Value, String Constant - RpRZyadwyO len=0 
' 0018     27 LABEL : Cell Value, String Constant - SYMsUKyjdqlV len=0 
' 0018     20 LABEL : Cell Value, String Constant - WSPVQ len=0 
' 0018     20 LABEL : Cell Value, String Constant - YUevh 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     1
... (truncated)

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