Spectre-Meltdown-Checker - Spectre & Meltdown Vulnerability/Mitigation Checker For Linux

A simple shell script to tell if your Linux installation is vulnerable against the 3 “speculative execution” CVEs:

CVE-2017-5753 bounds check bypass (Spectre Variant 1)

• Impact: Kernel & all software
• Mitigation: recompile software and kernel with a modified compiler that introduces the LFENCE opcode at the proper positions in the resulting code
• Performance impact of the mitigation: negligible

CVE-2017-5715: branch target injection (Spectre Variant 2)

• Impact: Kernel
• Mitigation 1: new opcode via microcode update that should be used by up to date compilers to protect the BTB (by flushing indirect branch predictors)
• Mitigation 2: introducing “retpoline” into compilers, and recompile software/OS with it
• Performance impact of the mitigation: high for mitigation 1, medium for mitigation 2, depending on your CPU

CVE-2017-5754: rogue data cache load (Meltdown)

• Impact: Kernel

• Mitigation: updated kernel (with PTI/KPTI patches), updating the kernel is enough

• Performance impact of the mitigation: low to medium
  Example of the output of the script:

  $ sudo ./spectre-meltdown-checker.sh
  Spectre and Meltdown mitigation detection tool v0.09

  CVE-2017-5753 [bounds check bypass] aka ‘Spectre Variant 1’

  • Kernel compiled with LFENCE opcode inserted at the proper places: NO (only 38 opcodes found, should be >= 60)
    > STATUS: VULNERABLE

  CVE-2017-5715 [branch target injection] aka ‘Spectre Variant 2’

  • Mitigation 1
  • Hardware (CPU microcode) support for mitigation: NO
  • Kernel support for IBRS: NO
  • IBRS enabled for Kernel space: NO
  • IBRS enabled for User space: NO
  • Mitigation 2
  • Kernel compiled with retpolines: NO
    > STATUS: VULNERABLE (IBRS hardware + kernel support OR kernel with retpolines are needed to mitigate the vulnerability)

  CVE-2017-5754 [rogue data cache load] aka ‘Meltdown’ aka ‘Variant 3’

  • Kernel supports Page Table Isolation (PTI): YES
  • PTI enabled and active: YES
    > STATUS: NOT VULNERABLE (PTI mitigates the vulnerability)

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