security-misc/debian/control

## Copyright (C) 2012 - 2014 Patrick Schleizer <adrelanos@riseup.net>
## See the file COPYING for copying conditions.

Source: security-misc
Section: misc
Priority: optional
Maintainer: Patrick Schleizer <adrelanos@riseup.net>
Build-Depends: debhelper (>= 9), genmkfile
Homepage: https://github.com/Whonix/security-misc
Vcs-Browser: https://github.com/Whonix/security-misc
Vcs-Git: https://github.com/Whonix/security-misc.git
Standards-Version: 3.9.8

Package: security-misc
Architecture: all
Depends: expect, ${misc:Depends}
Replaces: tcp-timestamps-disable
Description: enhances misc security settings
 The following settings are changed:
 .
 deactivates previews in Dolphin;
 deactivates previews in Nautilus;
 deactivates TCP timestamps;
 deactivates Netfilter's connection tracking helper;
 .
 TCP time stamps (RFC 1323) allow for tracking clock
 information with millisecond resolution. This may or may not allow an
 attacker to learn information about the system clock at such
 a resolution, depending on various issues such as network lag.
 This information is available to anyone who monitors the network
 somewhere between the attacked system and the destination server.
 It may allow an attacker to find out how long a given
 system has been running, and to distinguish several
 systems running behind NAT and using the same IP address. It might
 also allow one to look for clocks that match an expected value to find the
 public IP used by a user.
 .
 Hence, this package disables this feature by shipping the
 /etc/sysctl.d/tcp_timestamps.conf configuration file.
 .
 Note that TCP time stamps normally have some usefulness. They are
 needed for:
 .
 * the TCP protection against wrapped sequence numbers; however, to
   trigger a wrap, one needs to send roughly 2^32 packets in one
   minute:  as said in RFC 1700, "The current recommended default
   time to live (TTL) for the Internet Protocol (IP) [45,105] is 64".
   So, this probably won't be a practical problem in the context
   of Anonymity Distributions.
 .
 * "Round-Trip Time Measurement", which is only useful when the user
   manages to saturate their connection. When using Anonymity Distributions,
   probably the limiting factor for transmission speed is rarely the capacity
   of the user connection.
 .
 Netfilter's connection tracking helper module increases kernel attack
 surface by enabling superfluous functionality such as IRC parsing in
 the kernel. (!)
 .
 Hence, this package disables this feature by shipping the
 /etc/sysctl.d/nf_conntrack_helper.conf configuration file.