Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 30438b8f342615ae…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:39:49 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: 5de3e12c5d078ca37076daf7a1e43df7 SHA-1: 2b71c301a0683b88fd6e15071721be82a2feb5b3 SHA-256: 30438b8f342615aee99fd4954525c05eea5a1fb5fab140c5cfed643d64ce2e5a
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro-enabled workbook. Static analysis identified an Auto_Open defined name, which is a critical indicator of malicious intent as it allows for automatic execution of XLM macros upon opening. The presence of dangerous formula APIs like RUN further confirms the capability to execute arbitrary code. The macro sheet itself contains obfuscated strings and potentially malicious formulas, suggesting it's designed to download and execute a secondary 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) 6938 bytes
SHA-256: b41faab5504a35fbec604bf5ed372fccae5dad88d1b69c40067560383ca30b7a
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  tdyBwdDlSTh
' 0018     23 LABEL : Cell Value, String Constant - ASDuyNEy len=0 
' 0018     22 LABEL : Cell Value, String Constant - AuCxgDF len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A152 
' 0018     24 LABEL : Cell Value, String Constant - BXvGCFUWb len=0 
' 0018     25 LABEL : Cell Value, String Constant - cVIRkdgZbQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - djfTzLOKDH len=0 
' 0018     27 LABEL : Cell Value, String Constant - DkrYSwYjTsiB len=0 
' 0018     20 LABEL : Cell Value, String Constant - dZHBD len=0 
' 0018     24 LABEL : Cell Value, String Constant - FKWMDpNMt len=0 
' 0018     24 LABEL : Cell Value, String Constant - kDxuarCIe len=0 
' 0018     22 LABEL : Cell Value, String Constant - KGAbNKR len=0 
' 0018     21 LABEL : Cell Value, String Constant - nKWSQx len=0 
' 0018     25 LABEL : Cell Value, String Constant - rizIPvQkMK len=0 
' 0018     24 LABEL : Cell Value, String Constant - rppKxWnmX len=0 
' 0018     22 LABEL : Cell Value, String Constant - RqrAEtA len=0 
' 0018     20 LABEL : Cell Value, String Constant - sFAMl len=0 
' 0018     27 LABEL : Cell Value, String Constant - VvDKZOvLOFqP len=0 
' 0018     20 LABEL : Cell Value, String Constant - Wlmoc len=0 
' 0018     27 LABEL : Cell Value, String Constant - YiTiBHeSeodZ len=0 
' 0018     24 LABEL : Cell Value, String Constant - yNLhXMDAN len=0 
' 0018     23 LABEL : Cell Value, String Constant - ZUdwhCwa 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)