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Message-ID: <52E6D648.4060605@gmail.com> Date: Mon, 27 Jan 2014 21:57:28 +0000 From: Jakub Jozwiak <jozwiack@...il.com> To: full-disclosure@...ts.grok.org.uk Subject: [CVE-2014-1673] Check Point Session Authentication Agent vulnerability -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Product Information - ------------------- Check Point Session Authentication agent is a service that is installed on endpoint system in order to communicate with security gateway and allow it to request and obtain user's credentials. Session Authentication is a part of Legacy Authentication suite which provides different authentication methods to allow or deny access to network resources. R76 Security Gateway Technical Administration Guide[1] defines typical Session Authentication operation in the following way: 1. The user initiates a connection directly to the server 2. The Security Gateway intercepts the connection 3. The Session Authentication agent challenges the user for authentication data and returns this information to the gateway 4. If the authentication is successful, the Security Gateway allows the connection to pass through the gateway and continue to the target server Issue description - ----------------- Check Point Session Authentication agent version 4.1 and higher contains a flaw which is caused by lack of peer authentication in SSL communication. Encrypted communication between agent and security gateway has been introduced due to several issues (e.g. [2], [3]) which were revealed in the previous versions (4.0 and lower) of the product. Research showed that it is still possible to exploit previously known vulnerabilities - gateway impersonation and credential stealing - even though communication between agent and security gateway is utilizing SSL. Communication between Session Authentication agent and security gateway is performed using proprietary protocol. Since version 4.1 this communication scheme uses SSL as an underlying protocol to enable encryption of both protocol commands and user provided data. When SSL communication is negotiated between gateway and agent following cipher suites are visible in SSL Client Hello message as supported by Session Authentication agent: TLS_DH_anon_EXPORT_WITH_RC4_40_MD5 TLS_DH_anon_WITH_RC4_128_MD5 TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA TLS_DH_anon_WITH_DES_CBC_SHA TLS_DH_anon_WITH_3DES_EDE_CBC_SHA RFC2246 refers to listed cipher suites: "The following cipher suites are used for completely anonymous Diffie-Hellman communications in which neither party is authenticated. Note that this mode is vulnerable to man-in-the-middle attacks and is therefore deprecated." Taking into account above information it's possible to connect to Session Authentication agent from attacker's machine, initiate SSL-based communication, pass SSL handshake without being authenticated and use encrypted channel to control agent (e.g. prompt user for login and password). For attack to be successful attacker's machine must be allowed to connect to machine on which agent is running. Newer versions of Session Authentication agent include option to define three IP addresses which are allowed to issue authentication requests to agent. When this option is used it limits possibility of exploitation. Agent software has also "Allow any IP" option - when enabled attacker doesn't need to take additional measures in order to be able to connect to agent. Proof of Concept - ---------------- Attached PoC script simulates security gateway and allows credential stealing to be performed over encrypted communication channel against Session Authentication agent version 4.1 or higher. Affected versions - ----------------- Check Point Session Authentication agent, version 4.1 and higher Vendor response - --------------- Vendor has been informed about the issue on 8/8/2013. On 14/8/2013 vendor informed about expected fix date: 15/10/2013. On 28/10/2013 vendor informed that due to small user base and introduction of the Identity Awareness Software Blade[4] legacy session authentication will be deprecated in the major release of 2014. Additionally vendor published SecureKnowledge article[5]. Credits - ------- It should be noted that this finding is partially based on work of individuals who reported issues in the previous versions of Session Authentication agent as referenced in [2] and [3]. References - ---------- [1] https://sc1.checkpoint.com/documents/R76/CP_R76_SGW_WebAdmin/6721.htm [2] http://www.securityfocus.com/bid/1661/info [3] http://osvdb.org/show/osvdb/84985 [4] https://www.checkpoint.com/products/identity-awareness-software-blade/ [5] https://supportcenter.checkpoint.com/supportcenter/portal?eventSubmit_doGoviewsolutiondetails=&solutionid=sk98263 -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.0.20 (Darwin) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJS5tZHAAoJEO2gMNQgkP1iucwP/3ruK6iKIm6FvQ6DJsCVFMn1 98iWrXvU5jG0krKERu2Q2L3EkElvfq4reSeceIuVqpS20v69cCHCMKofFVaFeK2a 0Bo2zIqjnAr/T2/7DYwI1dgdZE4SAzcEscqeA8Zh6Hi04wME+sJpYxsq0lb7u2jY FuuqbUo5R4Y2hGXNoc0wKhiVhrOJ10DhvZaug+wbenX3721v+QqYzS+PUnql1WG3 4sSevvZM5Plb+aRhw6i4il/5UnwoWRW97YFL40AUgo/6JRClPInNdCSDiqXyLv50 riEe8g97mPf0EKjaaWD06iXuiVgA0rmcz9OzERnhmTtf0p8jdK/PVReDcyY6+68e DkeI/XRvsGQHP03fDSQaxlij/ZicXWcDfUwZyMEA8gEMg+0eaZ1OLdHrw8QWWoET 0XGfZ1jTVF9Df3sxmpXXIXH5kwjgDejR1JHap8vJqByPA6TBZI1Z7mCbqoR84b+Y 9jg8m5unGuEZTXQqJp50pDh+N/50zZ1YZVGDis2/5Vj0r2IXP3jse3RcjyC9kmgL edAh63OiP7/PvVebJRR7d9VUb9ECAbX0FBy6zc7DDvE7bveyYRlNDsLucDKH/x3S zAk7vupt3509tIOjBNrQM6kfiyWrJvrD59g8CidcjKD8+eiE44x17bwl6F1pXFT3 U4O8HMnMbOPUDugf3Nua =1P5f -----END PGP SIGNATURE----- View attachment "snauth-ssl.rb" of type "text/x-ruby-script" (7318 bytes) Download attachment "snauth-ssl.rb.sig" of type "application/octet-stream" (543 bytes) _______________________________________________ Full-Disclosure - We believe in it. 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