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Covert Timing Channel

CVE-2017-2624

Medium
5.9/10

Summary

It was found that xorg-x11-server before 1.19.0 including uses memcmp() to check the received MIT cookie against a series of valid cookies. If the cookie is correct, it is allowed to attach to the Xorg session. Since most memcmp() implementations return after an invalid byte is seen, this causes a time difference between a valid and invalid byte, which could allow an efficient brute force attack.

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

CWE-385 - Covert Timing Channel

Covert timing channels convey information by modulating some aspect of system behavior over time, so that the program receiving the information can observe system behavior and infer protected information.

References

Advisory Timeline

  • Published