ProactiveSecurityRoadmap

Revision 22 as of 2005-04-28 00:22:20

Clear message

Proactive Security Roadmap

Status

Introduction

Establish a strategy for implementing proactive security features in Ubuntu.

Rationale

(colin: a rationale would be nice, as to why you want to be proactive about things)

Scope and Use Cases

  • Privilege reduction
    • Run cron as non-root?
    • Run dhclient3 as non-root?
    • Run dhcpd3 as non-root?

    • Change unix_chkpwd from suid root to sgid shadow (see [http://bugs.debian.org/155583 #155583])

  • Compile-time stack protection?
  • Non-executable stack for i386?

  • MAC (SELinux) -> Separate BoF

  • Find ways to prevent exploitations of common vulnerabilities.

Implementation Plan

(colin: any idea how you want to implement it?)

Data Preservation and Migration

Does not apply here.

Packages Affected

Kernel:

  • Port the OpenWall patch that prevents exploitation of unsafe temporary file creation; it is really trivial; add a proc file to be able to enable/disable at runtime.

  • Provide a grsecurity kernel in universe, if a community member is interested to care about it; packaging is available.

  • Port some /proc restrictions which can be enabled/disabled at runtime.

  • Port randomisation patches: PID, TCP sequence numbers, TCP source ports
  • Delay the respawning of repeatedly crashing applications to prevent brute force attacks.

prelink:

  • Prelinked applications leave a huge /var/log/prelink.log which contains memory address; patch prelink to not dump addresses.

gcc:

  • If a community member is interested, we can provide SSP/Fortify/etc. gcc packages in universe, but we will not put them into main and use them as a default as long as upstream does not adopt a solution.

Outstanding Issues

(colin: is there anything that'd crop up as an issue?)

UDU BOF Agenda

  • Jamie will research whether there are things exploitable in exec-shield which aren't in PaX.
  • Evaluate chroot hardening patches.

UDU Pre-Work

  • Research privilege requirements of cron

    MartinPitt: Parsing the crontabs as normal user and introducing a minimal setuid wrapper for actually executing the commands as the target user will not help to improve security; the remaining stuff (timer and signal handling) does not accept user input and thus is not very error prone. I do not really have a good idea about this. (Note: atd also runs with root privileges, it just hides them a bit; I do not have an idea how to deroot this either, it's the same problem.)

  • Research privilege requirements of dhclient3

    MartinPitt: normal user with CAP_NET_RAW and CAP_NET_BIND_SERVICE; needs a suid wrapper to call /etc/dhcp3/dhclient-script; prototypical package available; pending security review of dhclient-script (proper quoting, etc.)

  • Research privilege requirements of dhcpd3

    MartinPitt: normal user with CAP_NET_RAW and CAP_NET_BIND_SERVICE for initialization phase; can be dropped after socket creation; prototypical package available

  • Search for implicit dependencies on inetd via netbase

    MartinPitt: I compiled a list of all packages in main which use inetd on page InetdUsage.

  • Determine requirements for compile-time stack protection in gcc (4.x?)

    MartinPitt: mudflap comes with gcc 4.0, but does not help in any way to improve proactive security; [http://www.research.ibm.com/trl/projects/security/ssp/ SSP] currently offers the [http://www.ida.liu.se/~johwi/research_publications/paper_ndss2003_john_wilander.pdf most effective protection], but does not (currently) work with 4.0 and is unlikely to be accepted upstream