Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a511a7d3e40cd7c7…

MALICIOUS

Office (OLE)

256.0 KB Created: 2020-07-29 08:27:40 Authoring application: Microsoft Excel First seen: 2020-09-15
MD5: 203ce34b9f2cf513fdc14ccc0a998bef SHA-1: 1046fa196fac0aa7c2f50f9b00f2dbc518d53360 SHA-256: a511a7d3e40cd7c7f2aad0b625e644cb16ad36eac9d311006f7fc2ea61b43658
180 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 macros, specifically an Auto_Open macro. The document body displays a message prompting the user to 'Enable Editing' and 'Enable Content', a common lure for macro execution. The presence of dangerous formula APIs and an environment evasion halt gate in the macro further indicates malicious intent. The primary technique observed is the use of a malicious attachment delivered via spearphishing.

Heuristics 4

  • 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.
  • XLM Auto_Open environment-evasion HALT gate high OLE_XLM_ENVIRONMENT_EVASION_HALT
    Excel 4.0 macro sheet auto-executes multiple GET.WORKSPACE / GET.WINDOW environment checks and halts execution when the host does not match the expected user environment. This is a common sandbox-evasion pattern in XLM malware and is stronger than a bare XLM macro-sheet indicator.
  • 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) 269830 bytes
SHA-256: 32ec1bb6531daa8a4e1964fee475b5bdbe950fc3b22d31923b620a220741605a
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  biBClwsFWT
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open hidden len=7 ptgNameX  NAMEIDX 4 
' 0018     20 LABEL : Cell Value, String Constant - BDxHi len=0 
' 0018     25 LABEL : Cell Value, String Constant - benKNlpuDd len=0 
' 0018     29 LABEL : Cell Value, String Constant -         hidden len=7 ptgRef3d  Sheet!DB2343 
' 0018     20 LABEL : Cell Value, String Constant - ePDRc len=0 
' 0018     27 LABEL : Cell Value, String Constant - EuibXgpkoGJw len=0 
' 0018     22 LABEL : Cell Value, String Constant - hGndbng len=0 
' 0018     22 LABEL : Cell Value, String Constant - iJaRBxP len=0 
' 0018     24 LABEL : Cell Value, String Constant - KcaKVguRT len=0 
' 0018     27 LABEL : Cell Value, String Constant - NqJOQeJVCbJp len=0 
' 0018     22 LABEL : Cell Value, String Constant - qfIwekv len=0 
' 0018     27 LABEL : Cell Value, String Constant - QifRszRUhNrN len=0 
' 0018     22 LABEL : Cell Value, String Constant - rEndkQF len=0 
' 0018     25 LABEL : Cell Value, String Constant - rfFNfBovdJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - WmhtsNCcB len=0 
' 0018     21 LABEL : Cell Value, String Constant - YMHZwJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - zBySvYR 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 : 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 LA
... (truncated)