Red Hat Enterprise Linux 8: Observable Discrepancy
CVE-2024-0553 is a high-severity observable discrepancy vulnerability in Red Hat Enterprise Linux 8 from Red Hat, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 1.61% chance of exploitation within 30 days, higher than 76% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update SIMATIC S7-1500 TM MFP - GNU/Linux subsystem to V1.1 or a later version.
- Update Gnutls to 3.8.3 or a later version.
- Read the advisory on gitlab.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.6 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8.8 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9.2 Extended Update Support | Not specified in the record | Not stated |
| Red Hat | RHODF-4.15-RHEL-9 | Not specified in the record | Not stated |
| Red Hat | RHOL-5.8-RHEL-9 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | before V1.1 | V1.1 |
| GNU | Gnutls | before 3.8.3 | 3.8.3 |
| Fedora Project | Fedora | 39 | Not stated |
| Red Hat | Enterprise Linux | 8.0; 9.0 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
A vulnerability was found in GnuTLS. The response times to malformed ciphertexts in RSA-PSK ClientKeyExchange differ from the response times of ciphertexts with correct PKCS#1 v1.5 padding. This issue may allow a remote attacker to perform a timing side-channel attack in the RSA-PSK key exchange, potentially leading to the leakage of sensitive data. CVE-2024-0553 is designated as an incomplete resolution for CVE-2023-5981.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Observable Discrepancy
The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.
How developers prevent this class of flaw
- Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- gitlab.com/gnutls/gnutls/-/issues/1522Exploit, Issue Tracking
Third-party and government advisories
- access.redhat.com/security/cve/CVE-2024-0553Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2258412Issue Tracking, Third Party Advisory
Other references
- access.redhat.com/errata/RHSA-2024:0533
- access.redhat.com/errata/RHSA-2024:0627
- access.redhat.com/errata/RHSA-2024:0796
- access.redhat.com/errata/RHSA-2024:1082
- access.redhat.com/errata/RHSA-2024:1108
- access.redhat.com/errata/RHSA-2024:1383
- access.redhat.com/errata/RHSA-2024:2094
- lists.gnupg.org/pipermail/gnutls-help/2024-January/004841.htmlMailing List
- openwall.com/lists/oss-security/2024/01/19/3
- lists.debian.org/debian-lts-announce/2024/02/msg00010.html
- lists.fedoraproject.org/archives/list/[email protected]/message/7ZEIOLORQ7N6WRPFXZSYDL…
- lists.fedoraproject.org/archives/list/[email protected]/message/GNXKVR5YNUEBNHAHM5GSYK…
- security.netapp.com/advisory/ntap-20240202-0011/
- cert-portal.siemens.com/productcert/html/ssa-794697.html
Other vulnerabilities in Red Hat Enterprise Linux 8
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.3 High severity
- 7.5 High severity
Recent Observable Discrepancy vulnerabilities
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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