Securing Alpine Linux

Securing Alpine Linux using Security Technical Implementation Guides (STIGs) involves several steps. STIGs are a series of security requirements and configurations that help to secure systems. While there might not be a specific STIG for Alpine Linux, you can follow general Linux hardening guidelines and apply the principles from other Linux STIGs. Here’s a step-by-step process:
== Step 1: Update and Upgrade System ==
1. Update package lists:
 
2. Upgrade installed packages:
 
== Step 2: Install Necessary Security Tools ==
1. Install the package:
 
2. Install other necessary security packages:
 
== Step 3: User and Access Management ==
1. Disable root login over SSH:
Edit :
 
Set the following parameter:
 PermitRootLogin no
2. Ensure password complexity:
Edit :
 
Add or update the following lines:
 minlen = 14
 dcredit = -1
 ucredit = -1
 ocredit = -1
 lcredit = -1
3. Lock unused system accounts:
 for user in `awk -F: '($3 < 1000) {print $1}' /etc/passwd`; do
 if [ $user ! "root" ]; then
 doas passwd -l $user
 doas chage -E 0 $user
 fi
 done
== Step 4: File System and Directory Permissions ==
1. Set appropriate permissions on important directories:
 doas chmod 700 /root
 doas chmod 600 /boot/grub/grub.cfg
 doas chmod 600 /etc/ssh/sshd_config
2. Configure mount options:
Edit :
 
Add `nosuid`, `nodev`, and `noexec` options to non-root partitions:
 /dev/sda1 /home ext4 defaults,nosuid,nodev,noexec 0 2
== Step 5: Network Security ==
1. Disable unnecessary services:
 
2. Configure firewall (iptables):
 
Create a basic firewall ruleset:
 
Example rules:
 *filter
 :INPUT DROP [0:0]
 :FORWARD DROP [0:0]
 :OUTPUT ACCEPT [0:0]
 -A INPUT -i lo -j ACCEPT
 -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
 -A INPUT -p tcp --dport 22 -j ACCEPT
 COMMIT
== Step 6: Logging and Auditing ==
1. Configure system logging:
Edit to ensure all log files are being captured:
 
Example configuration:
 *.info;mail.none;authpriv.none;cron.none /var/log/messages
 authpriv.* /var/log/secure
 mail.* -/var/log/maillog
 cron.* /var/log/cron
2. Set up audit rules:
Edit :
 
Example rules:
 -w /etc/passwd -p wa -k passwd_changes
 -w /etc/shadow -p wa -k shadow_changes
 -w /etc/group -p wa -k group_changes
== Step 7: Apply Kernel and Service Hardening ==
1. Disable unused filesystems:
Edit :
 
Add the following lines:
 install cramfs /bin/true
 install freevxfs /bin/true
 install jffs2 /bin/true
 install hfs /bin/true
 install hfsplus /bin/true
 install squashfs /bin/true
 install udf /bin/true
 install vfat /bin/true
2. Configure kernel parameters:
Edit :
 
Add or update the following parameters:
 net.ipv4.ip_forward = 0
 net.ipv4.conf.all.accept_source_route = 0
 net.ipv4.conf.all.accept_redirects = 0
 net.ipv4.conf.all.secure_redirects = 0
 net.ipv4.conf.all.log_martians = 1
 net.ipv4.conf.default.log_martians = 1
 net.ipv4.icmp_echo_ignore_broadcasts = 1
 net.ipv4.icmp_ignore_bogus_error_responses = 1
 net.ipv4.tcp_syncookies = 1
 net.ipv4.conf.all.send_redirects = 0
 net.ipv4.conf.default.send_redirects = 0
== Step 8: Regular Maintenance ==
1. Set up regular updates:
Create a cron job for regular updates:
 
Add the following line to update daily at 2 AM:
 0 2 * * * apk update && apk upgrade
2. Review and monitor logs regularly:
Ensure logs are rotated and reviewed frequently:
 
== Conclusion ==
This process provides a foundation for securing an Alpine Linux system. Regular reviews and updates, along with compliance with the latest security guidelines, are essential to maintaining a secure environment.
Category:Security