Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 55defe35f9114c0f…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:40:01 Authoring application: Microsoft Excel First seen: 2021-09-29
MD5: 1ed48716bbc9a5e20235aef617bdaf5e SHA-1: 7ad344d8d9a6a686c5c96779520d16e7dee04add SHA-256: 55defe35f9114c0f80376c2e63cc906b7f60fb1239ecb5731b41b0369b1c0d86
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 known technique for executing malicious code upon opening the workbook. The presence of dangerous formula APIs like RUN further indicates malicious intent. The macros are likely designed to download and execute a second-stage payload, although the specific payload and execution details are not fully discernible from the provided evidence.

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) 6531 bytes
SHA-256: ab54068433b99bcc3c22227a4eb319e84f4b22ecafa3971eb665c2bc717ad7a1
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 -  rkSYI
' 0018     25 LABEL : Cell Value, String Constant - aTBIabKreX len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D185 
' 0018     25 LABEL : Cell Value, String Constant - BvnBqqnLCj len=0 
' 0018     22 LABEL : Cell Value, String Constant - bwplmBR len=0 
' 0018     22 LABEL : Cell Value, String Constant - dEHPBWT len=0 
' 0018     25 LABEL : Cell Value, String Constant - DToVPmfOrv len=0 
' 0018     26 LABEL : Cell Value, String Constant - FlOMykASeBV len=0 
' 0018     21 LABEL : Cell Value, String Constant - hJeThj len=0 
' 0018     27 LABEL : Cell Value, String Constant - LsYfPHsqUHzx len=0 
' 0018     25 LABEL : Cell Value, String Constant - lzCunvlmiX len=0 
' 0018     21 LABEL : Cell Value, String Constant - mexvLh len=0 
' 0018     27 LABEL : Cell Value, String Constant - mhrDpDTNpSmG len=0 
' 0018     23 LABEL : Cell Value, String Constant - NnGVPkrc len=0 
' 0018     26 LABEL : Cell Value, String Constant - nSOSVtOiefM len=0 
' 0018     20 LABEL : Cell Value, String Constant - oHOER len=0 
' 0018     20 LABEL : Cell Value, String Constant - qfJKc len=0 
' 0018     25 LABEL : Cell Value, String Constant - TNzWnoPDSa len=0 
' 0018     25 LABEL : Cell Value, String Constant - TqkeGYBDwI len=0 
' 0018     23 LABEL : Cell Value, String Constant - XtNotToo len=0 
' 0018     27 LABEL : Cell Value, String Constant - yMtJNPnjkcpq len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZVhaSSb 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
' 00
... (truncated)

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