#VU1914 Information disclosure in OpenSSL - CVE-2016-0800

Vulnerability identifier: #VU1914

Vulnerability risk: Medium

CVSSv4.0: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:A/U:Green]

CVE-ID: CVE-2016-0800

CWE-ID: CWE-327

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
OpenSSL
Server applications / Encryption software

Vendor: OpenSSL Software Foundation

Description
The vulnerability allows a remote attacker to decrypt sensitive information.

The vulnerability exists due to usage of weak SSLv2 protocol, which requires to send a ServerVerify message before establishing that a client possesses certain plaintext RSA data. A remote attacker can decrypt TLS ciphertext data by leveraging a Bleichenbacher RSA padding oracle.

The vulnerability is dubbed "DROWN" attack.

Mitigation
Update to version 1.0.1s or 1.0.2g.

Vulnerable software versions

OpenSSL: 0.9.8l - 0.9.8p, 1.0.0d - 1.0.0p, 1.0.1l - 1.0.1, 1.0.2

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External links
https://drownattack.com/drown-attack-paper.pdf
https://openssl.org/news/secadv/20160301.txt

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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, a fully functional exploit for this vulnerability is available.