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Exposed IOCTL with Insufficient Access Control

CVE-2021-21787

Severity High
Score 8.8/10

Summary

A privilege escalation vulnerability exists in the way IOBit Advanced SystemCare Ultimate 14.2.0.220 driver handles Privileged I/O write requests. During IOCTL 0x9c40a0d8, the first dword passed in the input buffer is the device port to write to and the byte at offset 4 is the value to write via the OUT instruction. The OUT instruction can write one byte to the given I/O device port, potentially leading to escalated privileges of unprivileged users.

  • LOW
  • LOCAL
  • HIGH
  • CHANGED
  • NONE
  • LOW
  • HIGH
  • HIGH

CWE-782 - Exposed IOCTL with Insufficient Access Control

The software implements an IOCTL with functionality that should be restricted, but it does not properly enforce access control for the IOCTL.

References

Advisory Timeline

  • Published