CVE-2024-4603

Excessive time spent checking DSA keys and parameters

Severity Score

5.3

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

Attend

*SSVC

Descriptions

Issue summary: Checking excessively long DSA keys or parameters may be very
slow.

Impact summary: Applications that use the functions EVP_PKEY_param_check()
or EVP_PKEY_public_check() to check a DSA public key or DSA parameters may
experience long delays. Where the key or parameters that are being checked
have been obtained from an untrusted source this may lead to a Denial of
Service.

The functions EVP_PKEY_param_check() or EVP_PKEY_public_check() perform
various checks on DSA parameters. Some of those computations take a long time
if the modulus (`p` parameter) is too large.

Trying to use a very large modulus is slow and OpenSSL will not allow using
public keys with a modulus which is over 10,000 bits in length for signature
verification. However the key and parameter check functions do not limit
the modulus size when performing the checks.

An application that calls EVP_PKEY_param_check() or EVP_PKEY_public_check()
and supplies a key or parameters obtained from an untrusted source could be
vulnerable to a Denial of Service attack.

These functions are not called by OpenSSL itself on untrusted DSA keys so
only applications that directly call these functions may be vulnerable.

Also vulnerable are the OpenSSL pkey and pkeyparam command line applications
when using the `-check` option.

The OpenSSL SSL/TLS implementation is not affected by this issue.

The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.

Resumen del problema: la comprobación de claves o parámetros DSA excesivamente largos puede resultar muy lenta. Resumen de impacto: las aplicaciones que utilizan las funciones EVP_PKEY_param_check() o EVP_PKEY_public_check() para comprobar una clave pública de DSA o parámetros de DSA pueden experimentar grandes retrasos. Cuando la clave o los parámetros que se están verificando se obtuvieron de una fuente que no es confiable, esto puede dar lugar a una Denegación de Servicio. Las funciones EVP_PKEY_param_check() o EVP_PKEY_public_check() realizan varias comprobaciones de los parámetros DSA. Algunos de esos cálculos toman mucho tiempo si el módulo (parámetro `p`) es demasiado grande. Intentar utilizar un módulo muy grande es lento y OpenSSL no permitirá el uso de claves públicas con un módulo de más de 10.000 bits de longitud para la verificación de firmas. Sin embargo, las funciones de verificación de claves y parámetros no limitan el tamaño del módulo al realizar las verificaciones. Una aplicación que llama a EVP_PKEY_param_check() o EVP_PKEY_public_check() y proporciona una clave o parámetros obtenidos de una fuente que no es de confianza podría ser vulnerable a un ataque de denegación de servicio. OpenSSL no llama a estas funciones en claves DSA que no son de confianza, por lo que solo las aplicaciones que llaman directamente a estas funciones pueden ser vulnerables. También son vulnerables las aplicaciones de línea de comandos OpenSSL pkey y pkeyparam cuando se usa la opción `-check`. La implementación de OpenSSL SSL/TLS no se ve afectada por este problema. Los proveedores FIPS OpenSSL 3.0 y 3.1 se ven afectados por este problema.

*Credits: OSS-Fuzz, Tomas Mraz

CVSS Scores

CISAv3.1 5.3

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

* Common Vulnerability Scoring System

SSVC

Decision:Attend

Exploitation

None

Automatable

Yes

Tech. Impact

Partial

* Organization's Worst-case Scenario

Timeline

2024-05-07 CVE Reserved
2024-05-16 CVE Published
2024-10-14 CVE Updated
2024-10-15 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-606: Unchecked Input for Loop Condition
CWE-834: Excessive Iteration

CAPEC

References (7)

URL	Tag	Source
http://www.openwall.com/lists/oss-security/2024/05/16/2
https://security.netapp.com/advisory/ntap-20240621-0001

URL	Date	SRC

URL	Date	SRC
https://github.com/openssl/openssl/commit/3559e868e58005d15c6013a0c1fd832e51c73397	2024-06-21
https://github.com/openssl/openssl/commit/53ea06486d296b890d565fb971b2764fcd826e7e	2024-06-21
https://github.com/openssl/openssl/commit/9c39b3858091c152f52513c066ff2c5a47969f0d	2024-06-21
https://github.com/openssl/openssl/commit/da343d0605c826ef197aceedc67e8e04f065f740	2024-06-21

URL	Date	SRC
https://www.openssl.org/news/secadv/20240516.txt	2024-06-21

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.0.0 < 3.0.14 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.0.0 < 3.0.14"		en		Affected
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.1.0 < 3.1.6 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.1.0 < 3.1.6"		en		Affected
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.2.0 < 3.2.2 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.2.0 < 3.2.2"		en		Affected
OpenSSL Search vendor "OpenSSL"		OpenSSL Search vendor "OpenSSL" for product "OpenSSL"				>= 3.3.0 < 3.3.1 Search vendor "OpenSSL" for product "OpenSSL" and version " >= 3.3.0 < 3.3.1"		en		Affected