Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 279a5f838f2535bb…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:17 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: d28be511b65a6b8e4369917343896760 SHA-1: a64414fcf2e3b90b9304f43640e73db8220c8e1d SHA-256: 279a5f838f2535bbe786cc6599040d3876ab7a1264d4416bb2b65e08f8074908
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, and the use of dangerous formula APIs like RUN. This strongly suggests the macro is designed to execute arbitrary code upon opening the workbook. While no specific URLs or payloads were extracted, the presence of the RUN function points to a downloader or initial execution stage.

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) 6380 bytes
SHA-256: 02fcc9e5aaa03adcb88c3c80c5416bc37f6cec93559b517b21c3a084d77b98ea
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  pkf
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A131 
' 0018     21 LABEL : Cell Value, String Constant - aVDpEM len=0 
' 0018     27 LABEL : Cell Value, String Constant - BjwxpimeeNpc len=0 
' 0018     25 LABEL : Cell Value, String Constant - FxuxofzTBY len=0 
' 0018     26 LABEL : Cell Value, String Constant - GZARpVHIiAZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - jgxICz len=0 
' 0018     22 LABEL : Cell Value, String Constant - jNGXqDd len=0 
' 0018     24 LABEL : Cell Value, String Constant - KzPcgYplL len=0 
' 0018     25 LABEL : Cell Value, String Constant - NmNMKarEdU len=0 
' 0018     20 LABEL : Cell Value, String Constant - oWbNJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - RduzXL len=0 
' 0018     25 LABEL : Cell Value, String Constant - RwEUSyavsS len=0 
' 0018     25 LABEL : Cell Value, String Constant - saTLnHPdCf len=0 
' 0018     24 LABEL : Cell Value, String Constant - sIvnSiWoF len=0 
' 0018     27 LABEL : Cell Value, String Constant - SJUumybIvpXB len=0 
' 0018     24 LABEL : Cell Value, String Constant - svcamzhKv len=0 
' 0018     24 LABEL : Cell Value, String Constant - UkXuhwSbx len=0 
' 0018     24 LABEL : Cell Value, String Constant - VrCHXYxNT len=0 
' 0018     23 LABEL : Cell Value, String Constant - VvjFEMoK len=0 
' 0018     26 LABEL : Cell Value, String Constant - wCjLwddwidD len=0 
' 0018     23 LABEL : Cell Value, String Constant - WytGlMPx 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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