Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1acd4a0e35ec21db…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:41:29 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: cdeac463e907e0918baba09896db3068 SHA-1: 448f62ee66f8518c3c483220f05d3ea81108ab38 SHA-256: 1acd4a0e35ec21dbcd9e9c3dd15290caddf992766fedbe5d8fe6d32c3b6b4376
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The Auto_Open macro is configured to execute, and the presence of dangerous formula APIs suggests it is designed to perform malicious actions, likely to download and execute a secondary payload. No specific family could be identified.

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) 6429 bytes
SHA-256: c2e78cc6b3a2c4df26114a94d3aee5ebba7e557f56b59369bfed164b7ab87f06
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 -  jrojJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!F148 
' 0018     20 LABEL : Cell Value, String Constant - cdswJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - CSnIUy len=0 
' 0018     23 LABEL : Cell Value, String Constant - gLwaxdxl len=0 
' 0018     26 LABEL : Cell Value, String Constant - HSdIVRlCSvX len=0 
' 0018     26 LABEL : Cell Value, String Constant - hXVfzlTZwRY len=0 
' 0018     20 LABEL : Cell Value, String Constant - JWDke len=0 
' 0018     24 LABEL : Cell Value, String Constant - kVlyRXmDh len=0 
' 0018     23 LABEL : Cell Value, String Constant - lyUXeXwT len=0 
' 0018     27 LABEL : Cell Value, String Constant - mNMWeAhqIOSg len=0 
' 0018     22 LABEL : Cell Value, String Constant - obMUWiw len=0 
' 0018     24 LABEL : Cell Value, String Constant - OmSzwuDWv len=0 
' 0018     24 LABEL : Cell Value, String Constant - PGsFczjKS len=0 
' 0018     27 LABEL : Cell Value, String Constant - RgLHLWivvXtf len=0 
' 0018     24 LABEL : Cell Value, String Constant - RkYWkwZph len=0 
' 0018     21 LABEL : Cell Value, String Constant - rxsnAp len=0 
' 0018     25 LABEL : Cell Value, String Constant - RZVFNFlsXF len=0 
' 0018     20 LABEL : Cell Value, String Constant - urKSF len=0 
' 0018     27 LABEL : Cell Value, String Constant - wQCmToTwcxiG len=0 
' 0018     26 LABEL : Cell Value, String Constant - yBLOkoOeEuJ len=0 
' 0018     21 LABEL : Cell Value, String Constant - ZrMmVH 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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