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OS X Security. IT Security Analyst – Robert Vinson robert-vinson@uiowa.edu security@uiowa.edu. Reality Check. OS X had a similar number of vulnerabilities patched as Windows last year. Rootkits and worms have been developed for OS X. OS X machines can be and have been compromised.
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OS X Security IT Security Analyst – Robert Vinson robert-vinson@uiowa.edu security@uiowa.edu
Reality Check • OS X had a similar number of vulnerabilities patched as Windows last year. • Rootkits and worms have been developed for OS X. • OS X machines can be and have been compromised. • Move to x86 architecture makes OS X a more attractive target to exploit developers. • The Point: Use Anti-Virus, keep up to date on patches, etc.
Physical/Boot Security • Location – adequate visual surveillance • Service Provided – Affects which mitigation steps are realistic • Desktops • Open Firmware password • Case lock • Disable automatic root login in Single-User mode • Servers • Open Firmware password would hinder remote reboot
Software Updates • System Preferences -> Software Update • Servers should generally have this disabled. • Workstations should have daily update checks.
Disable Unneeded Services • Enumerate open ports • Netstat • Port scanner • Server Admin application • Disable unneeded services • Server Admin • /etc/hostconfig
SSH • Edit configuration file - /etc/sshd_config • Disallow root logins • Add usernames which should be able to connect via the AllowedUsers Directive. • Utilize firewall to restrict access to the daemon (e.g. perhaps restrict to University and Mediacom IP space only) • Add the service to xinetd and utilize xinetd throttling capabilites.
Permissions • OS X Permissions are weak. • Many world writable/readable directories and even executables! • Set more restrictive umask • Can be done via shell initialization files and/or globally • Audit permissions system wide • Good place to start: SUID files, world writable/files/directories
File Serving • AFP - allows for encrypted File transfer. • NFS - netboot mounts should be exported as read-only and squash root by default. • SMB – sharing in Windows environments.
Firewall • OS X uses the IPFW firewall. • Server Admin can be used to configure the firewall. • Greater control can be had by editing the /etc/ipfilter/ipfw.conf file. • IPFW utility can be scripted to open up ports at needed times, etc. • Utilize the firewall to scope down accessibility to services.
Logging • Syslog – configuration in /etc/syslog.conf • /var/log • Remote logging, as always, is a very good idea. • Syslog server can be restricted to only accept alerts from certain IP(s) or subnet(s). • Generally a good idea to have a separate partition for /var or even /var/log on a syslog server
User Authentication • Utilize Open Directory to set a password policy • Some Recommended settings • 8 char long passwords • Require alphanumeric • Enable expiring passwords • Enable account locking for failed attempts • Use pwpolicy to set policy
Misc. • File Vault • Disk Utility for fixing permissions
References/Resources • OS X Benchmark security document - http://www.cisecurity.org • NSA’s OS X Server Security Configuration guide - http://www.nsa.gov/snac • Apple – www.apple.com