Disable vsyscall mapping
An XCCDF Rule
Description
This config disables the vsyscall mapping at all. Attempts to use the vsyscalls will be reported to
dmesg, so that either old or malicious userspace programs can be identified.
This configuration is available from kernel 4.4.
The configuration that was used to build kernel is available at /boot/config-*.
To check the configuration value for CONFIG_LEGACY_VSYSCALL_NONE, run the following command:
grep CONFIG_LEGACY_VSYSCALL_NONE /boot/config-*
For each kernel installed, a line with value "y" should be returned.
warning alert: Warning
There is no remediation for this besides re-compiling the kernel with the appropriate value for the config.
Rationale
This will eliminate any risk of ASLR bypass due to the vsyscall fixed address mapping.
- ID
- xccdf_org.ssgproject.content_rule_kernel_config_legacy_vsyscall_none
- Severity
- Medium
- References
- Updated