diff --git a/debian/control b/debian/control index 6dd9b18..da55438 100644 --- a/debian/control +++ b/debian/control @@ -16,48 +16,46 @@ Architecture: all Depends: ${misc:Depends} Replaces: tcp-timestamps-disable Description: enhances misc security settings -- deactivates previews in Dolphin -- deactivates previews in Nautilus -- deactivates TCP timestamps -- deactivates Netfilter's connection tracking helper -. -Changes to the file browser only take effect for newly created user accounts. Not for -existing user accounts. This package is most useful to help Linux distribution -maintainers setting divergent defaults. -. -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 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. + 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 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.