Linux Kernel
CVE-2023-1998
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
|
| Impact | CVSS score of 5.6 (MEDIUM). Attack characteristics: local attack vector, high complexity, low privileges required, no user interaction not required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | Successful exploitation could compromise the medium-severity affected system. |
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Alert meAnalysisAI
The Linux kernel allows userspace processes to enable mitigations by calling prctl with PR_SET_SPECULATION_CTRL which disables the speculation feature as well as by using seccomp. Rated medium severity (CVSS 5.6). Public exploit code available.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
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Technical ContextAI · show details
This vulnerability is classified under CWE-1303. The Linux kernel allows userspace processes to enable mitigations by calling prctl with PR_SET_SPECULATION_CTRL which disables the speculation feature as well as by using seccomp. We had noticed that on VMs of at least one major cloud provider, the kernel still left the victim process exposed to attacks in some cases even after enabling the spectre-BTI mitigation with prctl. The same behavior can be observed on a bare-metal machine when forcing the mitigation to IBRS on boot command line. This happened because when plain IBRS was enabled (not enhanced IBRS), the kernel had some logic that determined that STIBP was not needed. The IBRS bit implicitly protects against cross-thread branch target injection. However, with legacy IBRS, the IBRS bit was cleared on returning to userspace, due to performance reasons, which disabled the implicit STIBP and left userspace threads vulnerable to cross-thread branch target injection against which STIBP protects. Affected products include: Linux Linux Kernel, Debian Debian Linux.
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Severity by source
AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
The Linux kernel allows userspace processes to enable mitigations by calling prctl with PR_SET_SPECULATION_CTRL which disables the speculation feature as well as by using seccomp. We had noticed that on VMs of at least one major cloud provider, the kernel still left the victim process exposed to attacks in some cases even after enabling the spectre-BTI mitigation with prctl. The same behavior can be observed on a bare-metal machine when forcing the mitigation to IBRS on boot command line.
This happened because when plain IBRS was enabled (not enhanced IBRS), the kernel had some logic that determined that STIBP was not needed. The IBRS bit implicitly protects against cross-thread branch target injection. However, with legacy IBRS, the IBRS bit was cleared on returning to userspace, due to performance reasons, which disabled the implicit STIBP and left userspace threads vulnerable to cross-thread branch target injection against which STIBP protects.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Exploit-DB
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.
Affected Products (CPE)NVD
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