#VU55665 Improper Certificate Validation in Go programming language - CVE-2021-34558
Vulnerability identifier: #VU55665
Vulnerability risk: Medium
CVSSv4.0: 7.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/U:Green]
CVE-ID:
CWE-ID:
CWE-295
Exploitation vector: Network
Exploit availability: Yes
Vulnerable software:
Go programming language
Universal components / Libraries /
Scripting languages
Vendor: Google
Description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to improper certificate verification in crypto/tls package in Go when processing X.509 certificates. The application does not properly assert that the type of public key in an X.509 certificate matches the expected type when doing a RSA based key exchange, allowing a malicious TLS server to cause a TLS client to panic.
Mitigation
Install updates from vendor's website.
Vulnerable software versions
Go programming language: 1.16 - 1.16.5
External links
https://groups.google.com/g/golang-announce
https://groups.google.com/g/golang-announce/c/n9FxMelZGAQ
https://golang.org/doc/devel/release#go1.16.minor
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3BA7MFVXRBEKRTLSLYDICTYCGEMK2HZ7/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/D7FRFM7WWR2JCT6NORQ7AO6B453OMI3I/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WXJ2MVMAHOIGRH37ZSFYC4EVWLJFL2EQ/
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JYIUSR4YP52PWG7YE7AA3DZ5OSURNFJB/
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.
