CVE-2024-36886
Description
A use-after-free (UAF) flaw exists in the Linux Kernel within the reassembly of fragmented TIPC messages, specifically in the tipc_buf_append() function. The issue results due to a lack of checks in the error handling cleanup and can trigger a UAF on "struct sk_buff", which may lead to remote code execution.
Statement
While the TIPC module is not loaded by default, this flaw might be used as one in a series of attacks. For that reason, and because of the possibility of remote code execution on systems where this module has been loaded, Red Hat assesses the impact of this flaw as Important.
Mitigation
The TIPC module is not automatically loaded in default configurations. When required, administrative privileges are required to explicitly load this module.
To determine if the TIPC module is loaded, use the following command:
# grep tipc /proc/modules
Look for output similar to the following:
tipc 479232 0 - Live 0xffffffffc1ba5000
ip6_udp_tunnel 16384 1 tipc, Live 0xffffffffc1b9b000
udp_tunnel 32768 1 tipc, Live 0xffffffffc1b8b000
Loading the module can be prevented with the following instructions:
# echo "install tipc /bin/true" >> /etc/modprobe.d/disable-tipc.conf
The system will need to be restarted if the module is loaded. In most circumstances, the TIPC kernel module will be unable to be unloaded while any network interfaces are active and the protocol is in use.
If the system requires this module to work correctly, this mitigation may not be suitable.
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 | 7.1 | 7.8 | 9.8 |
| Attack Vector | Adjacent Network | Local | Network |
| Attack Complexity | High | Low | Low |
| Privileges Required | Low | Low | None |
| 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:A/AC:H/PR:L/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:N/AC:L/PR:N/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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