Disable SSL/TLS Diffie-Hellman Modulus <= 1024 Bits (Logjam)
We were doing some penentration tests on our systems and we found out that on our FortiGate 200D which has SSL VPN enabled it is susceptible to the LongJam attack.
In the SSL VPN Settings, the below values have been set:
set algorithm high set sslv2 disable set sslv3 disable
In the Global COnfig, the below settings have been set:
set strong-crypto enable
Yet, when we perform the test again, the below output is presented to us:
Vulnerable connection combinations : SSL/TLS version : TLSv1.1 Cipher suite : TLS1_CK_DHE_RSA_WITH_AES_256_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.1 Cipher suite : TLS1_CK_DHE_RSA_WITH_3DES_EDE_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.1 Cipher suite : TLS1_CK_DHE_RSA_WITH_AES_128_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.1 Cipher suite : TLS1_CK_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.1 Cipher suite : TLS1_CK_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.0 Cipher suite : TLS1_CK_DHE_RSA_WITH_AES_256_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.0 Cipher suite : TLS1_CK_DHE_RSA_WITH_3DES_EDE_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.0 Cipher suite : TLS1_CK_DHE_RSA_WITH_AES_128_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.0 Cipher suite : TLS1_CK_DHE_RSA_WITH_CAMELLIA_256_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources) SSL/TLS version : TLSv1.0 Cipher suite : TLS1_CK_DHE_RSA_WITH_CAMELLIA_128_CBC_SHA Diffie-Hellman MODP size (bits) : 1024 Warning - This is a known static Oakley Group2 modulus. This may make the remote host more vulnerable to the Logjam attack. Logjam attack difficulty : Hard (would require nation-state resources)
Does anyone know how to disable the cipher in question or upgrade it to a 2048 bits?
Thank you in advance,
Thanasis