/Am-I-affected-by-Meltdown

Exploit / Proof-of-concept / checks whether system is affected by Variant 3: rogue data cache load (CVE-2017-5754), a.k.a MELTDOWN.

Primary LanguageC++BSD 2-Clause "Simplified" LicenseBSD-2-Clause

Am I affected by Meltdown?! Meltdown (CVE-2017-5754) checker

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What am I?

Proof-of-concept /

Exploit /

Checks whether system is affected by Variant 3: rogue data cache load (CVE-2017-5754), a.k.a MELTDOWN.

The basic idea is that user will know whether or not the running system is properly patched with something like KAISER patchset (https://lkml.org/lkml/2017/10/31/884) for example.

*** Only works on Linux for now ***

How it works?

It works by using /proc/kallsyms to find system call table and checking whether the address of a system call found by exploiting MELTDOWN match the respective one in /proc/kallsyms.

What to do when you face:

  • Unable to read /proc/kallsyms...

    That's because your system may be preventing the program from reading kernel symbols in /proc/kallsyms due to /proc/sys/kernel/kptr_restrict set to 1. The following command will do the tricky:

    sudo sh -c "echo 0  > /proc/sys/kernel/kptr_restrict"

  • Unable to read /boot/System.map-.

    That could probably be because your system not having /boot mounted. This program relies on that partition and thus you'd need to mount your /boot partition first.

Please open an issue if you have an idea on how to fallback to another approach in this scenario.

Getting started

Clone, then run make to compile the project, then run meltdown-checker:

git clone https://github.com/raphaelsc/Am-I-affected-by-Meltdown.git
cd ./Am-I-affected-by-Meltdown
make
taskset 0x1 ./meltdown-checker

Example output for a system affected by Meltdown:

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Checking whether system is affected by Variant 3: rogue data cache load (CVE-2017-5754), a.k.a MELTDOWN ...
Checking syscall table (sys_call_table) found at address 0xffffffffaea001c0 ...
0xc4c4c4c4c4c4c4c4 -> That's unknown
0xffffffffae251e10 -> That's SyS_write

System affected! Please consider upgrading your kernel to one that is patched with KAISER
Check https://security.googleblog.com/2018/01/todays-cpu-vulnerability-what-you-need.html for more details