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SSL/TLS 암호화 알고리즘(SSLCipherSuite)을 제외하는 방법

변군Dev 2023. 7. 5. 00:00
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SSL/TLS 암호화 알고리즘(SSLCipherSuite)을 제외하는 방법

  • 취약점 암호 스위트
TLS_RSA_WITH_AES_128_CBC_SHA
TLS_RSA_WITH_AES_256_CBC_SHA
TLS_RSA_WITH_AES_128_CBC_SHA256
TLS_RSA_WITH_AES_256_CBC_SHA256
TLS_RSA_WITH_AES_128_GCM_SHA256
TLS_RSA_WITH_AES_256_GCM_SHA384
  • Nginx에서 SSLCipherSuite에서 특정 알고리즘을 제외하는 방법
ssl_protocols TLSv1.2 TLSv1.3;
ssl_ciphers 'HIGH:!TLS_RSA_WITH_AES_128_CBC_SHA:!TLS_RSA_WITH_AES_256_CBC_SHA:!TLS_RSA_WITH_AES_128_CBC_SHA256:!TLS_RSA_WITH_AES_256_CBC_SHA256:!TLS_RSA_WITH_AES_128_GCM_SHA256:!TLS_RSA_WITH_AES_256_GCM_SHA384';
  • Apache에서 SSLCipherSuite에서 특정 알고리즘을 제외하는 방법
SSLProtocol all -SSLv3 -TLSv1 -TLSv1.1
SSLCipherSuite HIGH:!TLS_RSA_WITH_AES_128_CBC_SHA:!TLS_RSA_WITH_AES_256_CBC_SHA:!TLS_RSA_WITH_AES_128_CBC_SHA256:!TLS_RSA_WITH_AES_256_CBC_SHA256:!TLS_RSA_WITH_AES_128_GCM_SHA256:!TLS_RSA_WITH_AES_256_GCM_SHA384

 

[moz://a SSL] Configuration Generator

# generated 2023-07-04, Mozilla Guideline v5.7, Apache 2.4.41, OpenSSL 1.1.1, intermediate configuration
# https://ssl-config.mozilla.org/#server=apache&version=2.4.41&config=intermediate&openssl=1.1.1&guideline=5.7

# this configuration requires mod_ssl, mod_socache_shmcb, mod_rewrite, and mod_headers
<VirtualHost *:80>
    RewriteEngine On
    RewriteCond %{REQUEST_URI} !^/\.well\-known/acme\-challenge/
    RewriteRule ^(.*)$ https://%{HTTP_HOST}$1 [R=301,L]
</VirtualHost>

<VirtualHost *:443>
    SSLEngine on

    # curl https://ssl-config.mozilla.org/ffdhe2048.txt >> /path/to/signed_cert_and_intermediate_certs_and_dhparams
    SSLCertificateFile      /path/to/signed_cert_and_intermediate_certs_and_dhparams
    SSLCertificateKeyFile   /path/to/private_key

    # enable HTTP/2, if available
    Protocols h2 http/1.1

    # HTTP Strict Transport Security (mod_headers is required) (63072000 seconds)
    Header always set Strict-Transport-Security "max-age=63072000"
</VirtualHost>

# intermediate configuration
SSLProtocol             all -SSLv3 -TLSv1 -TLSv1.1
SSLCipherSuite          ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-CHACHA20-POLY1305
SSLHonorCipherOrder     off
SSLSessionTickets       off

SSLUseStapling On
SSLStaplingCache "shmcb:logs/ssl_stapling(32768)"
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OpenSSL을 사용하여 웹 사이트가 특정 암호화 알고리즘을 사용하는지 확인하는 방법

echo | openssl s_client -connect <웹사이트 주소>:<포트번호> -cipher <암호화 알고리즘>

실제 웹 사이트 주소와 포트 번호를 입력하여 위의 명령어를 실행하고, 각각의 암호화 알고리즘에 대해 확인해보세요.

예를 들어, TLS_RSA_WITH_AES_128_CBC_SHA 암호화 알고리즘을 확인하려면 다음과 같이 명령어를 실행할 수 있습니다.

echo | openssl s_client -connect <웹사이트 주소>:<포트번호> -cipher 'AES128-SHA'

 

echo | openssl s_client -connect sangchul.kr:443 -cipher 'AES128-SHA' 2>&1 | grep "Cipher is"
$ echo | openssl s_client -connect sangchul.kr:443 -cipher 'AES128-SHA' 2>&1 | grep "Cipher is"
New, SSLv3, Cipher is AES128-SHA

명령어를 실행하면 해당 암호화 알고리즘을 사용하는지 여부와 함께 SSL/TLS 연결에 대한 정보가 출력됩니다. 출력 결과에서 "Cipher is (NONE)"이라는 메시지가 나오면 해당 암호화 알고리즘을 사용하지 않는 것입니다.

 

cipher1
cipher2

 

Accepted: "Accepted"는 서버가 클라이언트의 제안을 수락하고 사용할 것을 의미합니다. 핸드셰이크 과정에서 클라이언트가 제안한 암호화 알고리즘, 키 교환 알고리즘 등이 서버에게 수락되었음을 나타냅니다. 이는 클라이언트와 서버 간의 암호화 통신에 사용될 알고리즘과 옵션이 서버 측에서 선택되었음을 의미합니다.

$ sslscan --no-failed sangchul.kr | grep Accepted
Accepted  TLSv1.2  128 bits  ECDHE-RSA-AES128-GCM-SHA256   Curve P-256 DHE 256
Accepted  TLSv1.2  128 bits  ECDHE-RSA-AES128-SHA256       Curve P-256 DHE 256
Accepted  TLSv1.2  128 bits  ECDHE-RSA-AES128-SHA          Curve P-256 DHE 256
Accepted  TLSv1.2  256 bits  ECDHE-RSA-AES256-SHA384       Curve P-256 DHE 256
Accepted  TLSv1.2  256 bits  ECDHE-RSA-AES256-SHA          Curve P-256 DHE 256
Accepted  TLSv1.2  128 bits  DHE-RSA-AES128-GCM-SHA256     DHE 2048 bits
Accepted  TLSv1.2  128 bits  DHE-RSA-AES128-SHA256         DHE 2048 bits
Accepted  TLSv1.2  128 bits  DHE-RSA-AES128-SHA            DHE 2048 bits
Accepted  TLSv1.2  256 bits  DHE-RSA-AES256-GCM-SHA384     DHE 2048 bits
Accepted  TLSv1.2  256 bits  DHE-RSA-AES256-SHA256         DHE 2048 bits
Accepted  TLSv1.2  256 bits  DHE-RSA-AES256-SHA            DHE 2048 bits
Accepted  TLSv1.2  128 bits  DHE-RSA-CAMELLIA128-SHA       DHE 2048 bits
Accepted  TLSv1.2  256 bits  DHE-RSA-CAMELLIA256-SHA       DHE 2048 bits
Accepted  TLSv1.2  256 bits  AES256-GCM-SHA384
Accepted  TLSv1.2  256 bits  AES256-SHA256
Accepted  TLSv1.2  256 bits  AES256-SHA
Accepted  TLSv1.2  256 bits  CAMELLIA256-SHA
Accepted  TLSv1.2  128 bits  AES128-GCM-SHA256
Accepted  TLSv1.2  128 bits  AES128-SHA256
Accepted  TLSv1.2  128 bits  AES128-SHA
Accepted  TLSv1.2  128 bits  CAMELLIA128-SHA
Accepted  TLSv1.2  ?? bits    TLS_RSA_WITH_SEED_CBC_SHA
Accepted  TLSv1.2  112 bits  TLS_RSA_WITH_3DES_EDE_CBC_SHA
Accepted  TLSv1.2  128 bits  TLS_RSA_WITH_IDEA_CBC_SHA
Accepted  TLSv1.1  256 bits  ECDHE-RSA-AES256-SHA          Curve P-256 DHE 256
Accepted  TLSv1.1  128 bits  DHE-RSA-AES128-SHA            DHE 2048 bits
Accepted  TLSv1.1  256 bits  DHE-RSA-AES256-SHA            DHE 2048 bits
Accepted  TLSv1.1  128 bits  DHE-RSA-CAMELLIA128-SHA       DHE 2048 bits
Accepted  TLSv1.1  256 bits  DHE-RSA-CAMELLIA256-SHA       DHE 2048 bits
Accepted  TLSv1.1  256 bits  AES256-SHA
Accepted  TLSv1.1  256 bits  CAMELLIA256-SHA
Accepted  TLSv1.1  128 bits  AES128-SHA
Accepted  TLSv1.1  128 bits  CAMELLIA128-SHA
Accepted  TLSv1.1  ?? bits    TLS_RSA_WITH_SEED_CBC_SHA
Accepted  TLSv1.1  112 bits  TLS_RSA_WITH_3DES_EDE_CBC_SHA
Accepted  TLSv1.1  128 bits  TLS_RSA_WITH_IDEA_CBC_SHA
Accepted  TLSv1.0  256 bits  ECDHE-RSA-AES256-SHA          Curve P-256 DHE 256
Accepted  TLSv1.0  128 bits  DHE-RSA-AES128-SHA            DHE 2048 bits
Accepted  TLSv1.0  256 bits  DHE-RSA-AES256-SHA            DHE 2048 bits
Accepted  TLSv1.0  128 bits  DHE-RSA-CAMELLIA128-SHA       DHE 2048 bits
Accepted  TLSv1.0  256 bits  DHE-RSA-CAMELLIA256-SHA       DHE 2048 bits
Accepted  TLSv1.0  256 bits  AES256-SHA
Accepted  TLSv1.0  256 bits  CAMELLIA256-SHA
Accepted  TLSv1.0  128 bits  AES128-SHA
Accepted  TLSv1.0  128 bits  CAMELLIA128-SHA
Accepted  TLSv1.0  ?? bits    TLS_RSA_WITH_SEED_CBC_SHA
Accepted  TLSv1.0  112 bits  TLS_RSA_WITH_3DES_EDE_CBC_SHA
Accepted  TLSv1.0  128 bits  TLS_RSA_WITH_IDEA_CBC_SHA

 

$sslscan --no-failed www.sangchul.kr | grep Accepted
Accepted  TLSv1.3  256 bits  TLS_AES_256_GCM_SHA384        Curve 25519 DHE 253
Accepted  TLSv1.3  256 bits  TLS_CHACHA20_POLY1305_SHA256  Curve 25519 DHE 253
Accepted  TLSv1.2  128 bits  ECDHE-RSA-AES128-GCM-SHA256   Curve 25519 DHE 253
Accepted  TLSv1.2  128 bits  ECDHE-RSA-AES128-SHA          Curve 25519 DHE 253
Accepted  TLSv1.2  128 bits  AES128-GCM-SHA256
Accepted  TLSv1.2  128 bits  AES128-SHA
Accepted  TLSv1.2  256 bits  ECDHE-RSA-AES256-GCM-SHA384   Curve 25519 DHE 253
Accepted  TLSv1.2  256 bits  ECDHE-RSA-AES256-SHA          Curve 25519 DHE 253
Accepted  TLSv1.2  256 bits  AES256-GCM-SHA384
Accepted  TLSv1.2  256 bits  AES256-SHA
Accepted  TLSv1.2  128 bits  ECDHE-RSA-AES128-SHA256       Curve 25519 DHE 253
Accepted  TLSv1.2  128 bits  AES128-SHA256
Accepted  TLSv1.2  256 bits  ECDHE-RSA-AES256-SHA384       Curve 25519 DHE 253
Accepted  TLSv1.2  256 bits  AES256-SHA256
Accepted  TLSv1.1  128 bits  AES128-SHA
Accepted  TLSv1.1  256 bits  ECDHE-RSA-AES256-SHA          Curve 25519 DHE 253
Accepted  TLSv1.1  256 bits  AES256-SHA
Accepted  TLSv1.0  128 bits  AES128-SHA
Accepted  TLSv1.0  256 bits  ECDHE-RSA-AES256-SHA          Curve 25519 DHE 253
Accepted  TLSv1.0  256 bits  AES256-SHA
Accepted  TLSv1.0  112 bits  TLS_RSA_WITH_3DES_EDE_CBC_SHA

 

$ sslscan --show-ciphers www.sangchul.kr

 

참고URL

- 암호 스위트 이름(cipher suite names) : https://www.openssl.org/docs/man1.1.1/man1/ciphers.html

 

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