Test your system for Spectre and Meltdown vulnerabilities
Following the outbreak of three processor vulnerabilities, known as Spectre and Meltdown; I have already patched my systems and whilst doing so, came across this useful script written by Speed47.
This script checks your system for the three vulnerabilities. I found it useful to check my systems were secure after applying kernel updates.
To run the script, use these commands below:
- Firstly download:
- Then run the script as sudo:
sudo sh spectre-meltdown-checker.sh
This is a quick summary of the vulnerabilities and their CVE numbers:
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
Disclaimer: Be careful when running script like these. Please check the script’s source code before running.