Cache Attacks in nss (Alpine package)

1) Cache Attacks

EUVDB-ID: #VU16219

Risk: Medium

CVSSv3.1: 7.3 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2018-12404

CWE-ID: CWE-300 - Channel Accessible by Non-Endpoint ('Man-in-the-Middle')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a downgrade attack on the server and decrypt private keys on the target system.

The vulnerability exists due to a core weakness in TLS that relates to the handshaking of the session key which is used within the tunnel during parallelisation of thousands of oracle queries that occurs using a cluster of TLS servers which share the same public key certificate. A remote attacker can mount a microarchitectural side channel attack against a vulnerable implementation, obtain a network man-in-the-middle position, obtain the relevant data to sign and trigger the victim server to decrypt ciphertexts chosen by the adversary to perform a downgrade attack.

Mitigation

Install update from vendor's website.

Vulnerable software versions

nss (Alpine package): 3.39-r0

External links

http://git.alpinelinux.org/aports/commit/?id=1cf2a95d5e12256524f77e43497146c98ea1cec2
http://git.alpinelinux.org/aports/commit/?id=10d9b859f21c3a2b7db4ec0d764cba419f4dfc4b
http://git.alpinelinux.org/aports/commit/?id=c857899e89107d1c9482cb0edd6d13091c0fd604

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.