Spectre & Meltdown Checker is a simple shell script to tell if your Linux installation is vulnerable against the 3 “speculative execution” CVEs that were made public early 2018.
Without options, it’ll inspect you currently running kernel. You can also specify a kernel image on the command line, if you’d like to inspect a kernel you’re not running.
The script will do its best to detect mitigations, including backported non-vanilla patches, regardless of the advertised kernel version number.
Summary of the CVEs in Spectre & Meltdown Checker
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
There are some other more generic BASH scripts for security scanning like:
– unix-privesc-check – Unix/Linux User Privilege Escalation Scanner
– LinEnum – Linux Enumeration & Privilege Escalation Tool
You can download Spectre & Meltdown Checker here:
Or read more here.