CVE-2024-41996
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Last Modified:
Description
A vulnerability was found in the Diffie-Hellman Ephemeral (DHE) Key Agreement Protocol, where a malicious client can exploit the server's public key validation process. By forcing the server to use DHE and validating the order of public keys, the client can trigger expensive server-side modular exponentiation calculations. This issue results in asymmetric resource consumption, potentially leading to a denial of service (DoS) attack by overwhelming the server with computationally intensive operations.
Statement
This vulnerability is classified with a Low severity rather than Moderate because it requires specific conditions to be exploitable. The attack depends on the server being configured to use DHE key exchange and perform public key order validation, which is not the default in many configurations. Additionally, while the attack can cause increased CPU usage, leading to a potential denial of service, it does not directly compromise the confidentiality, integrity, or availability of the data being exchanged. The impact is limited to resource exhaustion, and mitigations such as rate limiting, alternative key exchange methods, or disabling DHE can effectively reduce the attack surface, making it less impacted than issues that could lead to direct data breaches or system compromise.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Additional information
- Bugzilla 2307826: openssl: remote attackers (from the client side) to trigger unnecessarily expensive server-side DHE modular-exponentiation calculations
- CWE-295: Improper Certificate Validation
- FAQ: Frequently asked questions about CVE-2024-41996
External references
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
| Red Hat | NVD | |
|---|---|---|
CVSS v3 Base Score | 5.9 | N/A |
Attack Vector | Network | N/A |
Attack Complexity | High | N/A |
Privileges Required | None | N/A |
User Interaction | None | N/A |
Scope | Unchanged | N/A |
Confidentiality Impact | None | N/A |
Integrity Impact | None | N/A |
Availability Impact | High | N/A |
CVSS v3 Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Authentication
Technical Impact: Bypass Protection Mechanism; Gain Privileges or Assume Identity
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
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