diff --git a/debian/control b/debian/control index 3a6e623..abd1339 100644 --- a/debian/control +++ b/debian/control @@ -28,35 +28,6 @@ Description: enhances misc security settings restricts access to the root account; increases the amount of hashing rounds used by shadow; . - 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 @@ -155,3 +126,32 @@ Description: enhances misc security settings using su to gain root access or switch user accounts. . Logging into the root account from a terminal is prevented. + . + 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.