CVE-2024-50203
Description
A flaw was found in the Linux kernel. Specifically, within the Berkeley Packet Filter (BPF) component, an issue arises when BPF_TRAMP_F_CALL_ORIG is enabled. During address emission, an incorrect size calculation can lead to a heap buffer overflow, where more data is written to a memory block than it was allocated for. This could allow a privileged local attacker to potentially cause a denial of service or execute arbitrary code. The default kernel configuration restricts unprivileged users from using eBPF, which reduces the attack surface for this vulnerability.
Statement
The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.
For the Red Hat Enterprise Linux 8 to confirm the current state, inspect the sysctl with the command:
cat /proc/sys/kernel/unprivileged_bpf_disabled
The setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw.
Mitigation
Ensure the `kernel.unprivileged_bpf_disabled` sysctl is set to `1` to prevent unprivileged users from utilizing eBPF. This is the default configuration in Red Hat Enterprise Linux.
To verify the current setting:
bashIf the value is `0`, set it to `1` for the current session using:
cat /proc/sys/kernel/unprivileged_bpf_disabled
bashTo make this change persistent across reboots, add `kernel.unprivileged_bpf_disabled = 1` to a new file in `/etc/sysctl.d/` (e.g., `/etc/sysctl.d/99-disable-unprivileged-bpf.conf`) and then apply with `sysctl -p`. This action limits the functionality of unprivileged eBPF programs.
sysctl -w kernel.unprivileged_bpf_disabled=1
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).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.7 | 7.8 | 7.8 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | High | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
