CVE-2019-1543Not scoredCWE-327

CVE-2019-1543: ChaCha20-Poly1305 with long nonces

OpenSSL

Vendor fix available · Affected: OpenSSL · Exploitation: possible (1 to 10%)

Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.

5.7%probability of exploitation in the next 30 days

93rd percentile

050100

Higher than 93% of scored CVEs

Not scored yet. The CVE record carries no CVSS score.

DescriptionCVE.org

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).

Affected products1

From the CVE record. A product or version that is not listed is unknown, not unaffected.

OpenSSL · OpenSSLFixed 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)

On the Atlas

Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.

Open the Atlas

Exploitation: Possible (1 to 10%). EPSS between 1% and 10%.
CISA KEV: Not listed
Public check: No public nuclei template
Weakness: Use of a Broken or Risky Cryptographic Algorithm · Cryptography
Vendor: OpenSSL
Published: March 2019
Band: Possible (1 to 10%), March 2019

CoverageNo articles yet

No CyberSIXT article names CVE-2019-1543 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.

References

1 more reference is in the CVE record.