#VU21045 Padding oracle attack in OpenSSL - CVE-2019-1563

Vulnerability identifier: #VU21045

Vulnerability risk: Low

CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2019-1563

CWE-ID: CWE-310

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
OpenSSL
Server applications / Encryption software

Vendor: OpenSSL Software Foundation

Description

The vulnerability allows a remote attacker to perform padding oracle attack.

The vulnerability exists due to possibility to perform a Bleichenbacher padding oracle attack against the RSA key, in situations where an attacker receives automated notification of the success or failure of a decryption attempt an attacker. A remote attacker can send a very large number of messages to be decrypted, can recover a CMS/PKCS7 transported encryption key or decrypt any RSA encrypted message that was encrypted with the public RSA key.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

OpenSSL: 1.0.2h - 1.0.2p, 1.1.0h - 1.1.0, 1.1.1c - 1.1.1

---

External links
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=08229ad838c50f644d7e928e2eef147b4308ad64
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=631f94db0065c78181ca9ba5546ebc8bb3884b97
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=e21f8cf78a125cd3c8c0d1a1a6c8bb0b901f893f
https://www.openssl.org/news/secadv/20190910.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.