CVE-2021-3712 vulnerability in Canonical and Other Products
Published on August 24, 2021

Read buffer overruns processing ASN.1 strings

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).

Vendor Advisory Vendor Advisory Vendor Advisory NVD

Vulnerability Analysis

CVE-2021-3712 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity, and a high impact on availability.

Attack Vector:

NETWORK

Attack Complexity:

HIGH

Privileges Required:

NONE

User Interaction:

NONE

Scope:

UNCHANGED

Confidentiality Impact:

HIGH

Integrity Impact:

NONE

Availability Impact:

HIGH

Weakness Type

Out-of-bounds Read

The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.

Products Associated with CVE-2021-3712

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2021-3712 are published in these products:

Canonical Ubuntu Linux

OpenSSL

Debian Linux

NetApp Clustered Data Ontap

NetApp Clustered Data Ontap Antivirus Connector

NetApp E Series Santricity Os Controller

NetApp Hci Management Node

NetApp Manageability Software Development Kit

NetApp Santricity Smi S Provider

NetApp Solidfire

NetApp Storage Encryption

McAfee Epolicy Orchestrator

Tenable Sc

Oracle Mysql Enterprise Monitor

Oracle MySQL

Oracle Mysql Workbench

Oracle Zfs Storage Appliance Kit

Tenable Nessus Network Monitor

Oracle Essbase

Oracle Mysql Connectors

Oracle Peoplesoft Enterprise Peopletools

Oracle Secure Backup

Siemens Sinec Infrastructure Network Services

Oracle Jd Edwards World Security

Oracle Enterprise Session Border Controller

Oracle Enterprise Communications Broker

Oracle Communications Session Border Controller

Oracle Communications Cloud Native Core Security Edge Protection Proxy

Oracle Communications Unified Session Manager

Oracle Jd Edwards Enterpriseone Tools

Oracle Health Sciences Inform Publisher

Oracle Communications Cloud Native Core Console

Oracle Communications Cloud Native Core Unified Data Repository

Oracle

Siemens Simatic Pcs Neo

Siemens Sinec Nms

Siemens Sinema Remote Connect Server

Siemens Sinema Server

Siemens Tia Administrator

Affected Versions

OpenSSL:

Version Fixed in OpenSSL 1.1.1l (Affected 1.1.1-1.1.1k) is affected.
Version Fixed in OpenSSL 1.0.2za (Affected 1.0.2-1.0.2y) is affected.

Siemens BFCClient:

Before V2.17 is affected.

Siemens Industrial Edge - Machine Insight App:

Before * is affected.

Siemens Industrial Edge - PROFINET IO Connector:

Version All versions < V1.1.1 is affected.

Siemens RUGGEDCOM RM1224 LTE(4G) EU:

Version All versions < V7.1 is affected.

Siemens RUGGEDCOM RM1224 LTE(4G) NAM:

Version All versions < V7.1 is affected.

Siemens RUGGEDCOM ROX MX5000:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX MX5000RE:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1400:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1500:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1501:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1510:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1511:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1512:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1524:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX1536:

Before V2.15.0 is affected.

Siemens RUGGEDCOM ROX RX5000:

Before V2.15.0 is affected.

Siemens SCALANCE M804PB:

Version All versions < V7.1 is affected.

Siemens SCALANCE M812-1 ADSL-Router:

Version All versions < V7.1 is affected.

Siemens SCALANCE M812-1 ADSL-Router:

Version All versions < V7.1 is affected.

Siemens SCALANCE M816-1 ADSL-Router:

Version All versions < V7.1 is affected.

Siemens SCALANCE M816-1 ADSL-Router:

Version All versions < V7.1 is affected.

Siemens SCALANCE M826-2 SHDSL-Router:

Version All versions < V7.1 is affected.

Siemens SCALANCE M874-2:

Version All versions < V7.1 is affected.

Siemens SCALANCE M874-3:

Version All versions < V7.1 is affected.

Siemens SCALANCE M876-3:

Version All versions < V7.1 is affected.

Siemens SCALANCE M876-3 (ROK):

Version All versions < V7.1 is affected.

Siemens SCALANCE M876-4 (EU):

Version All versions < V7.1 is affected.

Siemens SCALANCE M876-4 (NAM):

Version All versions < V7.1 is affected.

Siemens SCALANCE MUM853-1 (EU):

Before V7.1 is affected.

Siemens SCALANCE MUM856-1 (EU):

Before V7.1 is affected.

Siemens SCALANCE MUM856-1 (RoW):

Before V7.1 is affected.

Siemens SCALANCE S615 LAN-Router:

Version All versions < V7.1 is affected.

Siemens SCALANCE SC622-2C:

Version All versions < V2.3 is affected.

Siemens SCALANCE SC632-2C:

Version All versions < V2.3 is affected.

Siemens SCALANCE SC636-2C:

Version All versions < V2.3 is affected.

Siemens SCALANCE SC642-2C:

Version All versions < V2.3 is affected.

Siemens SCALANCE SC646-2C:

Version All versions < V2.3 is affected.

Siemens SCALANCE W1748-1 M12:

Before V3.0.0 is affected.

Siemens SCALANCE W1748-1 M12:

Before V3.0.0 is affected.

Siemens SCALANCE W1788-1 M12:

Before V3.0.0 is affected.

Siemens SCALANCE W1788-2 EEC M12:

Before V3.0.0 is affected.

Siemens SCALANCE W1788-2 M12:

Before V3.0.0 is affected.

Siemens SCALANCE W1788-2IA M12:

Before V3.0.0 is affected.

Siemens SCALANCE W721-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W721-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W721-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W721-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W722-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W722-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W722-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W722-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W722-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W722-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45 (USA):

Before V6.6.0 is affected.

Siemens SCALANCE W734-1 RJ45 (USA):

Before V6.6.0 is affected.

Siemens SCALANCE W738-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W738-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W738-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W738-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W748-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W761-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W761-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W761-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W761-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 M12 EEC:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 M12 EEC:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 M12 EEC:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 M12 EEC:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45 (USA):

Before V6.6.0 is affected.

Siemens SCALANCE W774-1 RJ45 (USA):

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12 EEC:

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12 EEC:

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12 EEC (USA):

Before V6.6.0 is affected.

Siemens SCALANCE W778-1 M12 EEC (USA):

Before V6.6.0 is affected.

Siemens SCALANCE W786-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 SFP:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 SFP:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 SFP:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2 SFP:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2IA RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2IA RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2IA RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W786-2IA RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W788-1 RJ45:

Before V6.6.0 is affected.

Siemens SCALANCE W788-2 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W788-2 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W788-2 M12:

Before V6.6.0 is affected.

Siemens SCALANCE W788-2 M12:

Before V6.6.0 is affected.