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CVE-2021-3712

HIGHCVSS 7.4/10EPSS 50.44%

Last modified

CVE-2021-3712 is a high-severity vulnerability rated 7.4/10 on the CVSS scale. 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. EPSS estimates a 50.44% chance of exploitation in the next 30 days.

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).

Metrics

CVSS 3.1
7.4/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:H

EPSS Probability
50.44%

98.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
OpensslOpenssl>= 1.0.2, < 1.0.2za
OpensslOpenssl>= 1.1.1, < 1.1.1l
DebianDebian Linux9.0
DebianDebian Linux10.0
DebianDebian Linux11.0
NetappClustered Data OntapAll versions
NetappClustered Data Ontap Antivirus ConnectorAll versions
NetappE-Series Santricity Os Controller>= 11.0, <= 11.50.2
NetappHci Management NodeAll versions
NetappManageability Software Development KitAll versions
NetappSantricity Smi-S ProviderAll versions
NetappSolidfireAll versions
NetappStorage EncryptionAll versions
McafeeEpolicy Orchestrator< 5.10.0
McafeeEpolicy Orchestrator5.10.0
TenableNessus Network Monitor< 6.0.0
TenableTenable.Sc>= 5.16.0, <= 5.19.1
OracleEssbase< 11.1.2.4.047
OracleEssbase>= 21.0, < 21.3
OracleEssbase21.3
OracleMysql Connectors<= 8.0.27
OracleMysql Enterprise Monitor<= 8.0.25
OracleMysql Server>= 5.7.0, <= 5.7.35
OracleMysql Server>= 8.0.0, <= 8.0.26
OracleMysql Workbench<= 8.0.26
OraclePeoplesoft Enterprise Peopletools8.57
OraclePeoplesoft Enterprise Peopletools8.58
OraclePeoplesoft Enterprise Peopletools8.59
OracleSecure Backup18.1.0.1.0
OracleZfs Storage Appliance Kit8.8
SiemensSinec Infrastructure Network Services< 1.0.1.1
OracleCommunications Cloud Native Core Console1.9.0
OracleCommunications Cloud Native Core Security Edge Protection Proxy1.7.0
OracleCommunications Cloud Native Core Unified Data Repository1.15.0
OracleCommunications Session Border Controller8.4
OracleCommunications Session Border Controller9.0
OracleCommunications Unified Session Manager8.2.5
OracleCommunications Unified Session Manager8.4.5
OracleEnterprise Communications Broker3.2.0
OracleEnterprise Communications Broker3.3.0
OracleEnterprise Session Border Controller8.4
OracleEnterprise Session Border Controller9.0
OracleHealth Sciences Inform Publisher6.2.1.0
OracleHealth Sciences Inform Publisher6.3.1.1
OracleJd Edwards Enterpriseone Tools< 9.2.6.3
OracleJd Edwards World Securitya9.4

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-3712?
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).
How severe is CVE-2021-3712?
CVE-2021-3712 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 50.44% probability of exploitation in the next 30 days.
How do I fix CVE-2021-3712?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-3712?

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Source: NVD / NIST