CVE-2019-15212
Description
A use-after-free flaw was found in the RIO500 driver in the Linux kernel. The implementation of the driver did not consider that multiple RIO500 devices could be attached to the same system, simultaneously. When a second device connects, the system overwrites the data structures in use by the first allowing a local attacker to possibly create a use-after-free situation which can lead to memory corruption, system panic, or privilege escalation. The highest threat from this vulnerability is to system availability, although data integrity is also at risk as well.
Mitigation
As the rio500 module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions:
# echo "blacklist rio500" >> /etc/modprobe.d/rio-500.conf
# echo "install rio500 /bin/false" >> /etc/modprobe.d/rio-500.conf
The system will need to be restarted if the RIO500 modules are loaded. In most circumstances, the kernel modules will be unable to be unloaded while any devices or programs are using the USB device.
If the system requires this module to work correctly, this mitigation may not be suitable.
If you need further assistance, see KCS article https://access.redhat.com/solutions/41278 or contact Red Hat Global Support Services.
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 | 6.1 | 4.6 | N/A |
| Attack Vector | Local | Physical | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | Required | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | Low | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H
NVD: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Red Hat CVSS v3 Score Explanation
While Red Hat has not fully analyzed the effects of the flaw, it is possible that the exploit may result in memory corruption or privilege escalation in a worst-case scenario.
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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