CVE-2021-3712

Published: 24 August 2021

ASN.1 strings are represented internally within OpenSSL as an ASN1_STRING structure which contains a buffer holding the string data and a field holding the buffer length. This contrasts with normal C strings which are repesented as a buffer for the string data which is terminated with a NUL (0) byte. Although not a strict requirement, ASN.1 strings that are parsed using OpenSSL's own "d2i" functions (and other similar parsing functions) as well as any string whose value has been set with the ASN1_STRING_set() function will additionally NUL terminate the byte array in the ASN1_STRING structure. However, it is possible for applications to directly construct valid ASN1_STRING structures which do not NUL terminate the byte array by directly setting the "data" and "length" fields in the ASN1_STRING array. This can also happen by using the ASN1_STRING_set0() function. Numerous OpenSSL functions that print ASN.1 data have been found to assume that the ASN1_STRING byte array will be NUL terminated, even though this is not guaranteed for strings that have been directly constructed. Where an application requests an ASN.1 structure to be printed, and where that ASN.1 structure contains ASN1_STRINGs that have been directly constructed by the application without NUL terminating the "data" field, then a read buffer overrun can occur. The same thing can also occur during name constraints processing of certificates (for example if a certificate has been directly constructed by the application instead of loading it via the OpenSSL parsing functions, and the certificate contains non NUL terminated ASN1_STRING structures). It can also occur in the X509_get1_email(), X509_REQ_get1_email() and X509_get1_ocsp() functions. If a malicious actor can cause an application to directly construct an ASN1_STRING and then process it through one of the affected OpenSSL functions then this issue could be hit. This might result in a crash (causing a Denial of Service attack). It could also result in the disclosure of private memory contents (such as private keys, or sensitive plaintext). Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k). Fixed in OpenSSL 1.0.2za (Affected 1.0.2-1.0.2y).

Priority

Medium

CVSS 3 base score: 7.4

Status

Package Release Status
edk2
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo)
Released (2020.11-4ubuntu0.1)
Ubuntu 20.04 LTS (Focal Fossa)
Released (0~20191122.bd85bf54-2ubuntu3.3)
Ubuntu 18.04 LTS (Bionic Beaver) Needs triage

Ubuntu 16.04 ESM (Xenial Xerus) Needs triage

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist

nodejs
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Not vulnerable
(uses system openssl1.1)
Ubuntu 20.04 LTS (Focal Fossa) Not vulnerable
(uses system openssl1.1)
Ubuntu 18.04 LTS (Bionic Beaver) Not vulnerable
(uses system openssl1.0)
Ubuntu 16.04 ESM (Xenial Xerus) Not vulnerable
(uses system openssl)
Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable
(uses system openssl)
openssl
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo)
Released (1.1.1j-1ubuntu3.5)
Ubuntu 20.04 LTS (Focal Fossa)
Released (1.1.1f-1ubuntu2.8)
Ubuntu 18.04 LTS (Bionic Beaver)
Released (1.1.1-1ubuntu2.1~18.04.13)
Ubuntu 16.04 ESM (Xenial Xerus)
Released (1.0.2g-1ubuntu4.20+esm1)
Ubuntu 14.04 ESM (Trusty Tahr)
Released (1.0.1f-1ubuntu2.27+esm4)
Patches:
Upstream: https://git.openssl.org/?p=openssl.git;a=commit;h=c5dc9ab965f2a69bca964c709e648158f3e4cd67
openssl1.0
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 21.04 (Hirsute Hippo) Does not exist

Ubuntu 20.04 LTS (Focal Fossa) Does not exist

Ubuntu 18.04 LTS (Bionic Beaver)
Released (1.0.2n-1ubuntu5.7)
Ubuntu 16.04 ESM (Xenial Xerus) Does not exist

Ubuntu 14.04 ESM (Trusty Tahr) Does not exist