National Vulnerability Database

National Vulnerability Database

National Vulnerability
Database

CVE-2019-1543 Detail

Current Description

ChaCha20-Poly1305 is an AEAD cipher, and requires a unique nonce input for every encryption operation. RFC 7539 specifies that the nonce value (IV) should be 96 bits (12 bytes). OpenSSL allows a variable nonce length and front pads the nonce with 0 bytes if it is less than 12 bytes. However it also incorrectly allows a nonce to be set of up to 16 bytes. In this case only the last 12 bytes are significant and any additional leading bytes are ignored. It is a requirement of using this cipher that nonce values are unique. Messages encrypted using a reused nonce value are 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. Additionally the ignored bytes in a long nonce are not covered by the integrity guarantee of this cipher. Any application that relies on the integrity of these ignored leading bytes of a long nonce may be further affected. Any OpenSSL internal use of this cipher, including in SSL/TLS, is safe because no such use sets such a long nonce value. However user applications that use this cipher directly and set a non-default nonce length to be longer than 12 bytes may be vulnerable. OpenSSL versions 1.1.1 and 1.1.0 are affected by this issue. Due to the limited scope of affected deployments this has been assessed as low severity and therefore we are not creating new releases at this time. Fixed in OpenSSL 1.1.1c (Affected 1.1.1-1.1.1b). Fixed in OpenSSL 1.1.0k (Affected 1.1.0-1.1.0j).

Source:  MITRE
View Analysis Description

Impact

CVSS v3.0 Severity and Metrics:

Base Score: 7.4 HIGH
Vector: AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N (V3 legend)
Impact Score: 5.2
Exploitability Score: 2.2


Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): High
Availability (A): None

CVSS v2.0 Severity and Metrics:

Base Score: 5.8 MEDIUM
Vector: (AV:N/AC:M/Au:N/C:P/I:P/A:N) (V2 legend)
Impact Subscore: 4.9
Exploitability Subscore: 8.6


Access Vector (AV): Network
Access Complexity (AC): Medium
Authentication (AU): None
Confidentiality (C): Partial
Integrity (I): Partial
Availability (A): None
Additional Information:
Allows unauthorized disclosure of information
Allows unauthorized modification

References to Advisories, Solutions, and Tools

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Hyperlink Resource
http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00056.html
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=ee22257b1418438ebaf54df98af4e24f494d1809 Mailing List Patch Vendor Advisory
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=f426625b6ae9a7831010750490a5f0ad689c5ba3 Mailing List Patch Vendor Advisory
https://seclists.org/bugtraq/2019/Jul/3
https://www.debian.org/security/2019/dsa-4475
https://www.openssl.org/news/secadv/20190306.txt Vendor Advisory
https://www.oracle.com/technetwork/security-advisory/cpujul2019-5072835.html

Technical Details

Vulnerability Type (View All)

Known Affected Software Configurations Switch to CPE 2.3

Configuration 1 ( hide )
 cpe:/a:openssl:openssl
     Show Matching CPE(s)
From (including)
1.1.0
Up to (including)
1.1.0j
 cpe:/a:openssl:openssl
     Show Matching CPE(s)
From (including)
1.1.1
Up to (including)
1.1.1b


Change History

11 change records found - show changes

Quick Info

CVE Dictionary Entry:
CVE-2019-1543
NVD Published Date:
03/06/2019
NVD Last Modified:
06/03/2019