tinc Weak Salt Length Traffic Pattern Analysis Vulnerability
BID:3836
Info
tinc Weak Salt Length Traffic Pattern Analysis Vulnerability
| Bugtraq ID: | 3836 |
| Class: | Design Error |
| CVE: | |
| Remote: | Yes |
| Local: | No |
| Published: | Dec 29 2001 12:00AM |
| Updated: | Dec 29 2001 12:00AM |
| Credit: | Published by Jerome Etienne <[email protected]> on December 29, 2001. |
| Vulnerable: |
tinc tinc 1.0 pre4 tinc tinc 1.0 pre3 |
| Not Vulnerable: |
tinc tinc 1.0 pre5 |
Discussion
tinc Weak Salt Length Traffic Pattern Analysis Vulnerability
tinc is a Virtual Private Network (VPN) daemon designed for Linux and Unix based systems. It acts as a tunnel for a network interface, and embeds all communication into a sequence of encrypted UDP packets. This allows private network communication to occur through a larger network. tinc uses blowfish in cipher block chaining (CBC) mode to encrypt packets. The secret key is shared via a PKI-style handshake during the authentication process between two tinc daemons.
In order to avoid the detection of regular traffic patterns (specifically, the ability to recognize repeated, identical packets), tinc prepends a two byte random salt to each packet before it is encrypted. As a result of the birthday paradox, a collision in salt values is likely when approximately 2-300 identical packets are transmitted. Under some applications, this may result in traffic patterns being leaked to an outside observer of the communication.
tinc is a Virtual Private Network (VPN) daemon designed for Linux and Unix based systems. It acts as a tunnel for a network interface, and embeds all communication into a sequence of encrypted UDP packets. This allows private network communication to occur through a larger network. tinc uses blowfish in cipher block chaining (CBC) mode to encrypt packets. The secret key is shared via a PKI-style handshake during the authentication process between two tinc daemons.
In order to avoid the detection of regular traffic patterns (specifically, the ability to recognize repeated, identical packets), tinc prepends a two byte random salt to each packet before it is encrypted. As a result of the birthday paradox, a collision in salt values is likely when approximately 2-300 identical packets are transmitted. Under some applications, this may result in traffic patterns being leaked to an outside observer of the communication.
Exploit / POC
tinc Weak Salt Length Traffic Pattern Analysis Vulnerability
Currently the SecurityFocus staff are not aware of any exploits for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected] <mailto:[email protected]>.
Currently the SecurityFocus staff are not aware of any exploits for this issue. If you feel we are in error or are aware of more recent information, please mail us at: [email protected] <mailto:[email protected]>.
Solution / Fix
tinc Weak Salt Length Traffic Pattern Analysis Vulnerability
Solution:
An updated version has been released:
tinc tinc 1.0 pre4
tinc tinc 1.0 pre3
Solution:
An updated version has been released:
tinc tinc 1.0 pre4
-
tinc tinc-1.0pre5.tar.gz
http://tinc.nl.linux.org/packages/tinc-1.0pre5.tar.gz
tinc tinc 1.0 pre3
-
tinc tinc-1.0pre5.tar.gz
http://tinc.nl.linux.org/packages/tinc-1.0pre5.tar.gz