Logjam attacks-the new encryption bug affects a large number of users-bug warning-the black bar safety net

ID MYHACK58:62201562816
Type myhack58
Reporter 佚名
Modified 2015-05-24T00:00:00


Diffie-Hellman key exchange technology is one of the popular encryption algorithm which allows the Internet Protocol uses a shared key and a secure link. It is a multi-Protocol based including HTTPS, SSH, IPsec, SMTPS and some rely on the TLS Protocol. We have found a number of Diffie-Hellman key exchange vulnerability 1. Logjam attack on the TLS Protocol attacks. Logjam attack will allow one to use the middle attack hacking the TLS link encryption algorithm the output level down to 5 1 2. This will make the attacker to read and modify use this link for transmission of all data information. Logjam attack reminds us of the FREAK attack, but this attack using a TLS Protocol vulnerability rather than executable vulnerability and it attacks the Diffie-Hellman key exchange technology instead of the RSA key exchange technology. This attack will affect any support DHE_EXPORT encrypted server and will affect all modern web browsers. According to statistics, ranked top one million domain names have 8. 4%of websites are vulnerable. 2. From the other national competitors threats. In millions of HTTPS, SSH and VPN server use the Diffie-Hellman key exchange technology are all using the same initial sequence. Practitioners believe that as long as each link are using the new generation of key exchange information, so this mechanism is safe. No matter how the field screening process the first step in the destruction of a Diffie-Hellman linked the most effective algorithm is only based on these initial sequences. In the first step after the completion of one hacker can quickly for individual users link to attack. We of the TSL Protocol is the most commonly used 5 1 2 bit initial sequence were studied and the calculated results display the Logjam attack can make 8 0% TLS DHE_EXPORT Protocol Server link downgrade 2 0 per cent. Therefore, we further estimate an academic team to crack the 7 6 8-bit initial sequence and a national team able to crack the 1 0 2 4 bits of the initial sequence. In this casethe web serverthe use of the most common 1 0 2 4-bit initial sequence will allow the attacker to top one million for the HTTPS domain name of the communication line on the implementation of passive eavesdropping. The second one generates the sequence will allow the attacker in 6 6% of the VPN server and 2 6% of the SSH server of the communication line on the implementation of a passive decryption. To published the N. S. A. leaks, the interpretation indicates that the VPN proxy to attack with this attack the implementation process is consistent. Technical report We have published a technical report entitled the defective front-end encryption in the practice of Diffie-Hellman is how to fail on the contents of the report the focus is on these attacks is also about us how to hack the most common of the 5 1 2-bit Diffie-Hellman cryptographic combination of detailed information and we have been infected with the server of the evaluation. We also released some proof-of-concept example there is one for the TLS Protocol deployment Diffie-Hellman guidance tutorial. Who will be affected? Support DHE_EXPORT encryption algorithm website mail server and the other based on the TLS Protocol server there is a Logjam attack risk. We use the Internet a wide-area scan to evaluate what server-easy to be attacked. The Agreement may be Logjam attack HTTPS before a million domain names 8.4% HTTPS browser trusted sites 3.4% SMTP+StartTLSIPv4 address space 14.8% POP3SIPv4 address space 8.9% IMAPSIPv4 address space 8.4% Those using the above-described common share 1 0 2 4-bit Diffie-Hellman key collection site might be the hack of passive eavesdropping is very sensitive. Here we use a common the latest client(for example, the most common OpenSSH version, or the latest Chrome browser)and to show if a Protocol the use of a Single 1 0 2 4-digit key set is compromised then the various protocols is how to be infected. If the most common 1 0 2 4 bit key Pack crack will produce vulnerabilities of the Protocol as follows HTTPS before a million domain names 17.9% HTTPS browser trusted sites 6.6% SSHIPv4 address space 25.7% IKEv1(IPsec VPNs)for IPv4 address space 66.1% What I can do. If you have a server that is running... If you have a runningweb serveror mail server then you should disable the server to output a cipher Suite and generate a unique 2 0 4 8-bit Diffie-Hellman key set support. We have released one for the TLS Protocol deployment Diffie-Hellman guidance tutorial tutorial on the operation of each step for guidance. If you use SSH then you should move your servers and clients be upgraded to the latest version of OpenSSH and the latest version of OpenSSH used is elliptic curve Diffie-Hellman key exchange technology. If you use a browser... Please ensure that you install the latest version of the browser and often to check for updates. Google Chrome browser(including Android browser),Mozilla Firefox browser Microsoft's Internet Explorer and Apple's Safari browser for the Logjam attack for a patch repair. If you are a system administrator or Developer... Please make sure that you use all the TLS library have been updated and remove all less than 1 0 2 4-bit key Diffie-Hellman key set.