Denial of service in OpenSSL



Published: 2020-04-21
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2020-1967
CWE-ID CWE-476
Exploitation vector Network
Public exploit Public exploit code for vulnerability #1 is available.
Vulnerable software
Subscribe 		OpenSSL
Server applications / Encryption software

Vendor OpenSSL Software Foundation

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) NULL pointer dereference

EUVDB-ID: #VU27061

Risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-1967

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error within the SSL_check_chain() function during or after a TLS 1.3 handshake. A remote attacker can send an invalid or unrecognised signature algorithm and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

OpenSSL: 1.1.1d - 1.1.1f

External links

http://www.openssl.org/news/secadv/20200421.txt


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.



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