Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 af5ef0eff798a253…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:43:39 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 0a31d77437adebfc28106186bda9e567 SHA-1: 30c2161a63ef0b31fdf25fcf1875a799ccfcd1db SHA-256: af5ef0eff798a253710c6ae1365913be843439bce5375a9db188abbbe132e24c
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 defined name, which is a critical finding indicating automatic execution upon opening. The macros utilize dangerous formula APIs, suggesting an intent to execute arbitrary code. While the exact payload is not discernible from the provided evidence, the presence of Auto_Open and dangerous functions strongly points to a malicious execution chain.

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) 6852 bytes
SHA-256: afda1bc088771bdfa1fb2ebd26efb0912aa8c3d8e2c4beb35e634220f1d869ff
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 -  XnPEHlnp
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E174 
' 0018     21 LABEL : Cell Value, String Constant - BEWpXg len=0 
' 0018     23 LABEL : Cell Value, String Constant - cGogSAzG len=0 
' 0018     20 LABEL : Cell Value, String Constant - cUuWX len=0 
' 0018     23 LABEL : Cell Value, String Constant - ephiQmMa len=0 
' 0018     27 LABEL : Cell Value, String Constant - FsmuNTaMyapt len=0 
' 0018     25 LABEL : Cell Value, String Constant - gyQSaZflXs len=0 
' 0018     26 LABEL : Cell Value, String Constant - HikPTeKEyPc len=0 
' 0018     25 LABEL : Cell Value, String Constant - iaGTJOrlEN len=0 
' 0018     20 LABEL : Cell Value, String Constant - islCI len=0 
' 0018     21 LABEL : Cell Value, String Constant - jqKLGN len=0 
' 0018     26 LABEL : Cell Value, String Constant - KlbTXpzWbtg len=0 
' 0018     21 LABEL : Cell Value, String Constant - myQNxe len=0 
' 0018     27 LABEL : Cell Value, String Constant - NjAQsuYEtUdH len=0 
' 0018     23 LABEL : Cell Value, String Constant - QoHgjOFs len=0 
' 0018     20 LABEL : Cell Value, String Constant - RigfH len=0 
' 0018     23 LABEL : Cell Value, String Constant - tdXUWjIm len=0 
' 0018     22 LABEL : Cell Value, String Constant - UPCLNxT len=0 
' 0018     21 LABEL : Cell Value, String Constant - WPVXjz len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZpaPpmsjjNsv len=0 
' 0018     20 LABEL : Cell Value, String Constant - zRQFv 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 LAB
... (truncated)

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