I have a RHEL 9 server and our vulnerability scanner found the following two cipher suites on the server which we need to disable.
TLS 1.2 ciphers:
-
TLS_RSA_WITH_AES_256_CCM
- TLS_RSA_WITH_AES_256_GCM_SHA384
I'm having trouble on finding where to actually find these or disable them. I'm not very experienced in Linux.
As far as I know, this is not a web server. I checked the below locations:
- The /etc/crypto-policies/config
file just lists FUTURE
.
- Output of the command update-crypto-policies --show
is
FUTURE
- /etc/crypto-policies/policies/
lists nothing except a
modules
folder which also lists nothing.
- /etc/crypto-policies/state
has a file called CURRENT.pol
with the following info:
# Policy FUTURE dump
#
# Do not parse the contents of this file with automated tools,
# it is provided for review convenience only.
#
# Baseline values for all scopes:
cipher = AES-256-GCM AES-256-CCM CHACHA20-POLY1305 AES-256-CTR
group = X25519 SECP256R1 X448 SECP521R1 SECP384R1 FFDHE-3072 FFDHE-4096 FFDHE-6144 FFDHE-8192
hash = SHA2-256 SHA2-384 SHA2-512 SHA3-256 SHA3-384 SHA3-512 SHAKE-256
key_exchange = ECDHE DHE DHE-RSA PSK DHE-PSK ECDHE-PSK ECDHE-GSS DHE-GSS
mac = AEAD HMAC-SHA2-256 UMAC-128 HMAC-SHA2-384 HMAC-SHA2-512
protocol =
sign = ECDSA-SHA3-256 ECDSA-SHA2-256 ECDSA-SHA2-256-FIDO ECDSA-SHA3-384 ECDSA-SHA2-384 ECDSA-SHA3-512 ECDSA-SHA2-512 EDDSA-ED25519 EDDSA-ED25519-FIDO EDDSA-ED448 RSA-PSS-SHA3-256 RSA-PSS-SHA2-256 RSA-PSS-SHA3-384 RSA-PSS-SHA2-384 RSA-PSS-SHA3-512 RSA-PSS-SHA2-512 RSA-PSS-RSAE-SHA3-256 RSA-PSS-RSAE-SHA2-256 RSA-PSS-RSAE-SHA3-384 RSA-PSS-RSAE-SHA2-384 RSA-PSS-RSAE-SHA3-512 RSA-PSS-RSAE-SHA2-512 RSA-SHA3-256 RSA-SHA2-256 RSA-SHA3-384 RSA-SHA2-384 RSA-SHA3-512 RSA-SHA2-512
arbitrary_dh_groups = 1
min_dh_size = 3072
min_dsa_size = 3072
min_rsa_size = 3072
sha1_in_certs = 0
ssh_certs = 1
min_ec_size = 256
etm = ANY
__ems = DEFAULT
# Scope-specific properties derived for select backends:
cipher@gnutls = AES-256-GCM AES-256-CCM CHACHA20-POLY1305
protocol@gnutls = TLS1.3 TLS1.2 DTLS1.2
cipher@java-tls = AES-256-GCM AES-256-CCM CHACHA20-POLY1305
protocol@java-tls = TLS1.3 TLS1.2 DTLS1.2
cipher@krb5 = AES-256-GCM AES-256-CCM CHACHA20-POLY1305 AES-256-CTR AES-256-CBC
mac@krb5 = HMAC-SHA2-384 HMAC-SHA2-256 AEAD UMAC-128 HMAC-SHA2-512
protocol@libreswan = IKEv2
cipher@nss = AES-256-GCM AES-256-CCM CHACHA20-POLY1305
protocol@nss = TLS1.3 TLS1.2 DTLS1.2
cipher@openssl = AES-256-GCM AES-256-CCM CHACHA20-POLY1305
protocol@openssl = TLS1.3 TLS1.2 DTLS1.2
This is the only file I see that lists ciphers and other information. I tried commenting out AES-256-GCM
and AES-256-CCM
in the cipher
statement and restarted the server. But the vulnerability scanner is still recognizing those two cipher suites. I tried the same thing cipher@openssl
statement as well.
Appreciate any help on disabling these ciphers.
Asked by stipundos
(33 rep)
Apr 23, 2025, 12:41 PM
Last activity: Apr 23, 2025, 04:44 PM
Last activity: Apr 23, 2025, 04:44 PM