CVE-2015-4000
Description
A flaw was found in the way the TLS protocol composes the Diffie-Hellman exchange (for both export and non-export grade cipher suites). An attacker could use this flaw to downgrade a DHE connection to use export-grade key sizes, which could then be broken by sufficient pre-computation. This can lead to a passive man-in-the-middle attack in which the attacker is able to decrypt all traffic.
Statement
This issue affects the version of openssl and nss libraries as shipped with Red Hat Enterprise Linux 4, 5, 6 and 7. More information about this flaw is available at: https://bugzilla.redhat.com/show_bug.cgi?id=1223211#c4 and https://bugzilla.redhat.com/show_bug.cgi?id=1223211#c5.
Red Hat Enterprise Linux 4 is in Extended Life Cycle phase of the support and maintenance life cycle. This issue is not currently planned to be addressed in future updates of Red Hat Enterprise Linux 4.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert: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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 3.7 | 3.7 | 3.7 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | High | High |
| Privileges Required | None | None | None |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | None | None | None |
| Integrity Impact | Low | Low | Low |
| Availability Impact | None | None | None |
Vector
Red Hat: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
CVSS v2 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.3 | 4.3 | N/A |
| Attack Vector | Network | Network | N/A |
| Access Complexity | Medium | Medium | N/A |
| Authentication | None | None | N/A |
| Confidentiality Impact | Partial | None | N/A |
| Integrity Impact | None | Partial | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: AV:N/AC:M/Au:N/C:P/I:N/A:N
NVD: AV:N/AC:M/Au:N/C:N/I:P/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
The confidentiality of sensitive data may be compromised by the use of a broken or risky cryptographic algorithm.
Integrity
Technical Impact: Modify Application Data
The integrity of sensitive data may be compromised by the use of a broken or risky cryptographic algorithm.
Accountability,Non-Repudiation
Technical Impact: Hide Activities
If the cryptographic algorithm is used to ensure the identity of the source of the data (such as digital signatures), then a broken algorithm will compromise this scheme and the source of the data cannot be proven.
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