CVE-2021-3712

Name
CVE-2021-3712
Description
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).
NVD Severity
medium
Other trackers
Mailing lists
Exploits
Forges
GitHub (code, issues), Aports (code, issues)

References

Type URI
CONFIRM https://www.openssl.org/news/secadv/20210824.txt
CONFIRM https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=94d23fcff9b2a7a8368dfe52214d5c2569882c11
CONFIRM https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=ccb0a11145ee72b042d10593a64eaf9e8a55ec12
DEBIAN https://www.debian.org/security/2021/dsa-4963
MLIST https://lists.apache.org/thread.html/r18995de860f0e63635f3008fd2a6aca82394249476d21691e7c59c9e@%3Cdev.tomcat.apache.org%3E
MLIST http://www.openwall.com/lists/oss-security/2021/08/26/2
MLIST https://lists.apache.org/thread.html/rad5d9f83f0d11fb3f8bb148d179b8a9ad7c6a17f18d70e5805a713d1@%3Cdev.tomcat.apache.org%3E
CONFIRM https://security.netapp.com/advisory/ntap-20210827-0010/

Match rules

CPE URI Source package Min version Max version
cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* openssl >= 1.0.2 < 1.0.2za
cpe:2.3:a:openssl:openssl:*:*:*:*:*:*:*:* openssl >= 1.1.1 < 1.1.1l

Vulnerable and fixed packages

Source package Branch Version Maintainer Status
openssl 3.14-main 1.1.1l-r0 Timo Teras <timo.teras@iki.fi> fixed
openssl 3.13-main 1.1.1l-r0 Timo Teras <timo.teras@iki.fi> fixed
openssl 3.12-main 1.1.1l-r0 Timo Teras <timo.teras@iki.fi> fixed
openssl 3.11-main 1.1.1l-r0 Timo Teras <timo.teras@iki.fi> fixed