SSL 3.0 の脆弱性 POODLE の確認と対応

脆弱性の内容

グーグルのセキュリティチーム、SSL 3.0の脆弱性「POODLE」を説明 - ZDNet Japan

SSL 3.0 で接続できるかの確認

• openssl コマンドのs_client, -ssl3オプションを使って確認できる．

接続できるとき

[root@hogehoge ~]# openssl s_client -connect 127.0.0.1:443 -ssl3 | cat -n

<<< snip >>>

    48  ---
    49  New, TLSv1/SSLv3, Cipher is RC4-SHA
    50  Server public key is 2048 bit
    51  Secure Renegotiation IS NOT supported
    52  Compression: NONE
    53  Expansion: NONE
    54  SSL-Session:
    55      Protocol  : SSLv3
    56      Cipher    : RC4-SHA
    57      Session-ID: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    58      Session-ID-ctx:
    59      Master-Key: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
    60      Key-Arg   : None
    61      Krb5 Principal: None
    62      PSK identity: None
    63      PSK identity hint: None
    64      Start Time: 1413353391
    65      Timeout   : 7200 (sec)
    66      Verify return code: 0 (ok)
    67  ---

<<< snip >>>

接続できないとき

[root@hogehoge ~]# openssl s_client -connect 127.0.0.1:443 -ssl3 | cat -n

<<< snip >>>

     8  ---
     9  New, (NONE), Cipher is (NONE)
    10  Secure Renegotiation IS NOT supported
    11  Compression: NONE
    12  Expansion: NONE
    13  SSL-Session:
    14      Protocol  : SSLv3
    15      Cipher    : 0000
    16      Session-ID:
    17      Session-ID-ctx:
    18      Master-Key:
    19      Key-Arg   : None
    20      PSK identity: None
    21      PSK identity hint: None
    22      SRP username: None
    23      Start Time: 1413352529
    24      Timeout   : 7200 (sec)
    25      Verify return code: 0 (ok)
    26  ---

<<< snip >>>

対応

nginx

• http://nginx.org/en/docs/http/ngx_http_ssl_module.html#ssl_protocols
• ssl_protocolsディレクティブにSSLv3を指定しない．

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

Apache

• http://httpd.apache.org/docs/2.2/mod/mod_ssl.html#sslprotocol
• SSLProtocolでSSLv3を無効にする．

SSLProtocol All -SSLv2 -SSLv3

ZWS (Zeus Web Server)

• 使ってる人いないと思うけど一応．
• global.cfgのディレクティブtuning!support_ssl3で無効にできる．

tuning!support_ssl3 no