Описание
Issue summary: A TLS 1.3 connection using certificate compression can be
forced to allocate a large buffer before decompression without checking
against the configured certificate size limit.
Impact summary: An attacker can cause per-connection memory allocations of
up to approximately 22 MiB and extra CPU work, potentially leading to
service degradation or resource exhaustion (Denial of Service).
In affected configurations, the peer-supplied uncompressed certificate
length from a CompressedCertificate message is used to grow a heap buffer
prior to decompression. This length is not bounded by the max_cert_list
setting, which otherwise constrains certificate message sizes. An attacker
can exploit this to cause large per-connection allocations followed by
handshake failure. No memory corruption or information disclosure occurs.
This issue only affects builds where TLS 1.3 certificate compression is
compiled in (i.e., not OPENSSL_NO_COMP_ALG) and at least one compression
algorithm (brotli, zlib, or zstd) is available, and where the compression
extension is negotiated. Both clients receiving a server CompressedCertificate
and servers in mutual TLS scenarios receiving a client CompressedCertificate
are affected. Servers that do not request client certificates are not
vulnerable to client-initiated attacks.
Users can mitigate this issue by setting SSL_OP_NO_RX_CERTIFICATE_COMPRESSION
to disable receiving compressed certificates.
The FIPS modules in 3.6, 3.5, 3.4 and 3.3 are not affected by this issue,
as the TLS implementation is outside the OpenSSL FIPS module boundary.
OpenSSL 3.6, 3.5, 3.4 and 3.3 are vulnerable to this issue.
OpenSSL 3.0, 1.1.1 and 1.0.2 are not affected by this issue.
A flaw was found in OpenSSL. A remote attacker can exploit this vulnerability by sending a specially crafted CompressedCertificate message during the TLS 1.3 handshake. This can cause excessive per-connection memory allocations, leading to resource exhaustion and a Denial of Service (DoS) for affected clients and servers. This issue occurs when TLS 1.3 certificate compression is enabled and negotiated.
Отчет
This vulnerability is rated Low for Red Hat products. The flaw in OpenSSL 3.3, 3.4, 3.5, and 3.6 allows an attacker to cause excessive memory allocation during TLS 1.3 handshake with certificate compression, potentially leading to a Denial of Service. This affects both clients and servers in mutual TLS scenarios where certificate compression is negotiated. Servers not requesting client certificates are not vulnerable to client-initiated attacks.
Меры по смягчению последствий
To mitigate this issue, disable the reception of compressed certificates by setting the SSL_OP_NO_RX_CERTIFICATE_COMPRESSION option in OpenSSL configurations. This will prevent the vulnerable code path from being exercised.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | edk2 | Not affected | ||
| Red Hat Enterprise Linux 10 | shim | Not affected | ||
| Red Hat Enterprise Linux 10 | shim-unsigned-aarch64 | Not affected | ||
| Red Hat Enterprise Linux 10 | shim-unsigned-x64 | Not affected | ||
| Red Hat Enterprise Linux 6 | openssl | Not affected | ||
| Red Hat Enterprise Linux 7 | openssl | Not affected | ||
| Red Hat Enterprise Linux 7 | ovmf | Not affected | ||
| Red Hat Enterprise Linux 8 | compat-openssl10 | Not affected | ||
| Red Hat Enterprise Linux 8 | edk2 | Not affected | ||
| Red Hat Enterprise Linux 8 | mingw-openssl | Not affected |
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Дополнительная информация
Статус:
EPSS
5.9 Medium
CVSS3
Связанные уязвимости
Issue summary: A TLS 1.3 connection using certificate compression can be forced to allocate a large buffer before decompression without checking against the configured certificate size limit. Impact summary: An attacker can cause per-connection memory allocations of up to approximately 22 MiB and extra CPU work, potentially leading to service degradation or resource exhaustion (Denial of Service). In affected configurations, the peer-supplied uncompressed certificate length from a CompressedCertificate message is used to grow a heap buffer prior to decompression. This length is not bounded by the max_cert_list setting, which otherwise constrains certificate message sizes. An attacker can exploit this to cause large per-connection allocations followed by handshake failure. No memory corruption or information disclosure occurs. This issue only affects builds where TLS 1.3 certificate compression is compiled in (i.e., not OPENSSL_NO_COMP_ALG) and at least one compression algorithm (bro...
Issue summary: A TLS 1.3 connection using certificate compression can be forced to allocate a large buffer before decompression without checking against the configured certificate size limit. Impact summary: An attacker can cause per-connection memory allocations of up to approximately 22 MiB and extra CPU work, potentially leading to service degradation or resource exhaustion (Denial of Service). In affected configurations, the peer-supplied uncompressed certificate length from a CompressedCertificate message is used to grow a heap buffer prior to decompression. This length is not bounded by the max_cert_list setting, which otherwise constrains certificate message sizes. An attacker can exploit this to cause large per-connection allocations followed by handshake failure. No memory corruption or information disclosure occurs. This issue only affects builds where TLS 1.3 certificate compression is compiled in (i.e., not OPENSSL_NO_COMP_ALG) and at least one compression algorithm (bro
Issue summary: A TLS 1.3 connection using certificate compression can ...
Issue summary: A TLS 1.3 connection using certificate compression can be forced to allocate a large buffer before decompression without checking against the configured certificate size limit. Impact summary: An attacker can cause per-connection memory allocations of up to approximately 22 MiB and extra CPU work, potentially leading to service degradation or resource exhaustion (Denial of Service). In affected configurations, the peer-supplied uncompressed certificate length from a CompressedCertificate message is used to grow a heap buffer prior to decompression. This length is not bounded by the max_cert_list setting, which otherwise constrains certificate message sizes. An attacker can exploit this to cause large per-connection allocations followed by handshake failure. No memory corruption or information disclosure occurs. This issue only affects builds where TLS 1.3 certificate compression is compiled in (i.e., not OPENSSL_NO_COMP_ALG) and at least one compression algorithm (...
Уязвимость параметра max_cert_list сжатия сертификатов в TLS 1.3 библиотеки OpenSSL, позволяющая нарушителю вызвать отказ в обслуживании
EPSS
5.9 Medium
CVSS3