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Unrestricted Upload of File with Dangerous Type

CVE-2021-38305

High
7.8/10

Summary

23andMe Yamale before 3.0.8 allows remote attackers to execute arbitrary code via a crafted schema file. The schema parser uses eval as part of its processing, and tries to protect from malicious expressions by limiting the builtins that are passed to the eval. When processing the schema, each line is run through Python's eval function to make the validator available. A well-constructed string within the schema rules can execute system commands; thus, by exploiting the vulnerability, an attacker can run arbitrary code on the image that invokes Yamale.

  • LOW
  • LOCAL
  • HIGH
  • UNCHANGED
  • REQUIRED
  • NONE
  • HIGH
  • HIGH

CWE-434 - Unrestricted Upload of File with dangerous type

'Unrestricted file upload with dangerous type' attacks involve an attacker uploading or transferring files of dangerous types to the server. The severity of such an attack depends upon the execution mechanism and the storage location of the uploaded file. Thus, it may range from simple defacement to arbitrary file execution, and complete system takeover.

References

Advisory Timeline

  • Published