Information disclosure in OpenSSL ChaCha20-Poly1305 cipher



Published: 2019-03-06
Risk Low
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2019-1543
CWE-ID CWE-327
Exploitation vector Network
Public exploit N/A
Vulnerable software
Subscribe 		OpenSSL
Server applications / Encryption software

Vendor OpenSSL Software Foundation

Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Use of a broken or risky cryptographic algorithm

EUVDB-ID: #VU17908

Risk: Low

CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-1543

CWE-ID: CWE-327 - Use of a Broken or Risky Cryptographic Algorithm

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to encrypted data.

The vulnerability exists due to incorrect implementation of the ChaCha20-Poly1305 cipher. For messages, encrypted with this cipher, a reused nonce value is used that is susceptible to serious confidentiality and integrity attacks. If an application changes the default nonce length to be longer than 12 bytes and then makes a change to the leading bytes of the nonce expecting the new value to be a new unique nonce then such an application could inadvertently encrypt messages with a reused nonce.

This vulnerability does not affect internal usage of the cipher within OpenSSL. However if an application uses this cipher directly and sets a non-default nonce length to be longer than 12 bytes, it may be vulnerable.

Mitigation

The vendor has issued patches that are available from the repository.

Vulnerable software versions

OpenSSL: 1.1.0 - 1.1.1b

External links

http://www.openssl.org/news/secadv/20190306.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.



###SIDEBAR###