Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c8f6ed5f2df6f51c…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:41:49 Authoring application: Microsoft Excel First seen: 2021-10-14
MD5: 202d4e7fe3709858f5cb1b5151ca3fcc SHA-1: 3429943c12046aee2fe4dccf3aadc2ae42aea0bf SHA-256: c8f6ed5f2df6f51cfb2ff02ba43d717da426d61c0a516a2a7346d99cc57405cb
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a critical finding indicating potential malicious execution. The presence of dangerous formula APIs within the XLM macro suggests an attempt to run arbitrary code. While the exact payload is not discernible from the provided evidence, the mechanism points to a macro-based attack, likely delivered as a spearphishing attachment.

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) 6714 bytes
SHA-256: 15f102886900389f5c825ad571766249e06a23c9e95332b9c8cb057d5faab7be
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 -  OUIWg
' 0018     25 LABEL : Cell Value, String Constant - AkuyhoGbZp len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A160 
' 0018     21 LABEL : Cell Value, String Constant - BqOQeo len=0 
' 0018     20 LABEL : Cell Value, String Constant - dGfDA len=0 
' 0018     22 LABEL : Cell Value, String Constant - FazDUbp len=0 
' 0018     23 LABEL : Cell Value, String Constant - GfViXVaX len=0 
' 0018     25 LABEL : Cell Value, String Constant - gxuTdKBblm len=0 
' 0018     27 LABEL : Cell Value, String Constant - IcqvLRQJaxZa len=0 
' 0018     21 LABEL : Cell Value, String Constant - jfGfGs len=0 
' 0018     20 LABEL : Cell Value, String Constant - LheUy len=0 
' 0018     25 LABEL : Cell Value, String Constant - MYVCHVEUUZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - qaYOmR len=0 
' 0018     23 LABEL : Cell Value, String Constant - qYHCiVYR len=0 
' 0018     25 LABEL : Cell Value, String Constant - RXprFYfhLc len=0 
' 0018     24 LABEL : Cell Value, String Constant - SLdaAfDiL len=0 
' 0018     24 LABEL : Cell Value, String Constant - UfmGjDqpy len=0 
' 0018     21 LABEL : Cell Value, String Constant - vlWIro len=0 
' 0018     23 LABEL : Cell Value, String Constant - VrqxqqUX len=0 
' 0018     23 LABEL : Cell Value, String Constant - WMYRlKRX len=0 
' 0018     22 LABEL : Cell Value, String Constant - yqVKQGw len=0 
' 0018     24 LABEL : Cell Value, String Constant - zHFQwtTXF 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     10 LABELSST
... (truncated)

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