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Several issues have been discovered in Tor, a connection-based low-latency anonymous communication system, resulting in information leaks. . - ------------------------------------------------------------------------- Debian Security Advisory DSA-2993-1 This email address is being protected from spambots. You need JavaScript enabled to view it. http://www.debian.org/security/ Peter Palfrader July 31, 2014 http://www.debian.org/security/faq - ------------------------------------------------------------------------- Package : tor CVE ID : CVE-2014-5117 Several issues have been discovered in Tor, a connection-based low-latency anonymous communication system, resulting in information leaks. o Relay-early cells could be used by colluding relays on the network to tag user circuits and so deploy traffic confirmation attacks [CVE-2014-5117]. The updated version emits a warning and drops the circuit upon receiving inbound relay-early cells, preventing this specific kind of attack. Please consult the following advisory for more details about this issue: https://blog.torproject.org/tor-security-advisory-relay-early-traffic-confirmation-attack/ o A bug in the bounds-checking in the 32-bit curve25519-donna implementation could cause incorrect results on 32-bit implementations when certain malformed inputs were used along with a small class of private ntor keys. This flaw does not currently appear to allow an attacker to learn private keys or impersonate a Tor server, but it could provide a means to distinguish 32-bit Tor implementations from 64-bit Tor implementations. The following additional security-related improvements have been implemented: o As a client, the new version will effectively stop using CREATE_FAST cells. While this adds computational load on the network, this approach can improve security on connections where Tor's circuit handshake is stronger than the available TLS connection security levels. o Prepare clients to use fewerentry guards by honoring the consensus parameters. The following article provides some background: https://blog.torproject.org/improving-tors-anonymity-changing-guard-parameters/ For the stable distribution (wheezy), these problems have been fixed in version 0.2.4.23-1~deb7u1. For the testing distribution (jessie) and the unstable distribution (sid), these problems have been fixed in version 0.2.4.23-1. For the experimental distribution, these problems have been fixed in version 0.2.5.6-alpha-1. We recommend that you upgrade your tor packages. Further information about Debian Security Advisories, how to apply these updates to your system and frequently asked questions can be found at: http://www.debian.org/security/ Mailing list: This email address is being protected from spambots. You need JavaScript enabled to view it. . Enhance your Tor installations to address vulnerabilities highlighted in Debian Security Notice DSA-2993-1 concerning data exposure.. Tor Security Advisory, Debian DSA-2993, Connections Security. . Severity: Critical. LinuxSecurity.com Team
Jul 31, 2014
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