CVE-2022-49029
Description
A flaw was found in the hwmon (hardware monitoring) subsystem of the Linux kernel, specifically within the ibmpex driver. This vulnerability is a Use-After-Free (UAF) error, which occurs when the system attempts to use memory that has already been released. An attacker with administrative privileges could exploit this flaw, potentially leading to a system crash or other unpredictable behavior.
Statement
This issue is considered to be a moderate impact flaw, as the exploitation for this will need an ADMIN (or ROOT) privilege (PR:H).
Mitigation
To mitigate this issue, prevent the `ibmpex` kernel module from loading by creating a blacklist file. This action may impact systems that rely on IBM pSeries hardware monitoring.
Create a file named `/etc/modprobe.d/blacklist-ibmpex.conf` with the following content:
blacklist ibmpex
install ibmpex /bin/true
After creating the file, regenerate the initramfs and reboot the system for the changes to take effect. For example, on Red Hat Enterprise Linux:
bash
draco-update initramfs
reboot
Note that a system reboot is required for the mitigation to be fully applied.
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 | 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
The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
Confidentiality
Technical Impact: Read Memory
Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
Integrity,Confidentiality,Availability
Technical Impact: Execute Unauthorized Code or Commands
If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.
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