| name | cis-ubuntu1604-v200-1-5-2 |
| description | Ensure address space layout randomization (ASLR) is enabled |
| category | cis-storage |
| version | 2.0.0 |
| author | cyberstrike-official |
| tags | ["cis","ubuntu","linux","ubuntu-16.04","aslr","kernel","hardening","exploit-mitigation"] |
| cis_id | 1.5.2 |
| cis_benchmark | CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 |
| tech_stack | ["ubuntu","linux"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - 1.5.2
Profile Applicability
- Level 1 - Server
- Level 1 - Workstation
Description
Address space layout randomization (ASLR) is an exploit mitigation technique which randomly arranges the address space of key data areas of a process.
Rationale
Randomly placing virtual memory regions will make it difficult to write memory page exploits as the memory placement will be consistently shifting.
Audit Procedure
Command Line
Run the following commands and verify output matches:
sysctl kernel.randomize_va_space
Expected output: kernel.randomize_va_space = 2
grep -Es "^\s*kernel\.randomize_va_space\s*=\s*([0-1]|[3-9]|[1-9][0-9]+)" /etc/sysctl.conf /etc/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /run/sysctl.d/*.conf
Nothing should be returned.
Expected Result
kernel.randomize_va_space should be set to 2. No overriding configurations should exist in sysctl configuration files.
Remediation
Command Line
Set the following parameter in /etc/sysctl.conf or a /etc/sysctl.d/* file ending in .conf:
kernel.randomize_va_space = 2
Run the following script to comment out entries that override the default setting of kernel.randomize_va_space:
#!/usr/bin/bash
for file in /etc/sysctl.conf /etc/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /run/sysctl.d/*.conf; do
if [ -f "$file" ]; then
grep -Esq "^\s*kernel\.randomize_va_space\s*=\s*([0-1]|[3-9]|[1-9][0-9]+)" "$file" && sed -ri 's/^\s*kernel\.randomize_va_space\s*=\s*([0-1]|[3-9]|[1-9][0-9]+)/# &/gi' "$file"
fi
done
