PROTOCOL DESIGN FLAWS
Research by the CoreLabs team has led many companies to improve the security of their products. Below are just a few examples of some of the vulnerabilities we have discovered.
VULNERABILITY IN MYSQL AUTHENTICATION
The "MySQL Database Engine" (versions 3.2 up to 3,x) uses an authentication scheme designed to prevent the flow of plain text passwords over a network and the storage of the passwords in plain text. For that purpose, a challenge-response mechanism for authentication has been implemented on all versions of MySQL.
However, this authentication mechanism is not cryptographically strong. Each time a user executes this mechanism, information allowing an attacker to recover the user's password is leaked. Using an attack of CoreLabs design, which exploits geometric properties of the authentication mechanism, an eavesdropper is able to recover the user's password after witnessing a few executions of this protocol. An attacker is then able to authenticate himself to the database engine, impersonating a valid user.
TIMING ANALYSIS OF KEYSTROKES IN SSH
In SSH's interactive mode, keystrokes are sent to the server as the user types. An attacker is then able to discern the delay between each keystroke. CoreLabs was able to determine how this information can help an attacker guess the complete flow of data typed by a client.
First, we gather information about the user's typing habits, i.e., a transcript of a text typed by the user and the delays between each keystroke. Then, by modeling the user's typing process as Hidden Markov Chains, we are able to use a k-Viterbi algorithm to evaluate the best-hidden process to produce the observed delays between keystrokes. We can then produce a list of the most probable transcripts for the observation.
In parallel to this project, [STW01] presents another attack that exploits this SSH vulnerability with reduced scope. The attack from [STW01] aims only at recovering user passwords and not at recovering complete transcripts of their SSH connections.
WEAK AUTHENTICATION AND INTEGRITY MECHANISMS IN SECURE PROTOCOLS
Several cryptographic protocols use block ciphers and simple integrity functions like checksum or CRC to preserve the privacy, integrity and authentication security of communication channels. We recently studied known protocols like Kerberos and SSH, which use or used these types of schemes, for weaknesses. Our analysis produced an efficient attack to the SSH1 protocol ([FuKa:1998,FuKaPa:1999]) that permitted an attacker to insert arbitrary data in a connection without any previous knowledge.
VULNERABILITY IN MYSQL AUTHENTICATION
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Arce, Iván | Azubel Friedman, Agustín | Kargieman, Emiliano | Richarte, Gerardo | Sarraute, Carlos | Waissbein, Ariel; " MySQL Authentication Design Flaw ", (CoreLabs Technical Report), 2001 . |
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Azubel Friedman, Agustín | Kargieman, Emiliano | Richarte, Gerardo | Sarraute, Carlos | Waissbein, Ariel; " Code for Exploiting a MySQL Authentication Vulnerability ", (Squeak changeset), 2000 . |
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Azubel Friedman, Agustín | Kargieman, Emiliano | Richarte, Gerardo | Sarraute, Carlos | Waissbein, Ariel; " Vulnerability Report for MySQL Authentication ", (Advisory), 2000 . |
WEAK AUTHENTICATION AND INTEGRITY MECHANISMS IN SECURE PROTOCOLS
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Kargieman, Emiliano | Futoransky, Ariel; " ssh insertion attack ", (Advisory), 1998 . |