CVE-2019-19523
Description
A flaw was found in the Linux kernel’s implementation for ADU devices from Ontrak Control Systems, where an attacker with administrative privileges and access to a local account could pre-groom the memory and physically disconnect or unload a module. The attacker must be able to access either of these two events to trigger the use-after-free, and then race the access to the use-after-free, to create a situation where key USB structs can be manipulated into corrupting memory.
Mitigation
As the system module will be auto-loaded when a device that uses the driver is attached (via USB), its use can be disabled by preventing the module from loading with the following instructions:
# echo "install adutux /bin/true" >> /etc/modprobe.d/disable-adutux.conf
The system will need to be restarted if the adutux module are loaded. In most circumstances, the kernel modules will be unable to be unloaded while any hardware is in use.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.8 | 4.6 | N/A |
| Attack Vector | Local | Physical | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | None | N/A |
| Integrity Impact | High | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Integrity,Other
Technical Impact: Alter Execution Logic; Unexpected State
The attacker can gain access to otherwise unauthorized resources.
Integrity,Other
Technical Impact: Modify Application Data; Modify Files or Directories; Modify Memory; Other
Race conditions such as this kind may be employed to gain read or write access to resources which are not normally readable or writable by the user in question.
Integrity,Other
Technical Impact: Other
The resource in question, or other resources (through the corrupted one), may be changed in undesirable ways by a malicious user.
Non-Repudiation
Technical Impact: Hide Activities
If a file or other resource is written in this method, as opposed to in a valid way, logging of the activity may not occur.
Non-Repudiation,Other
Technical Impact: Other
In some cases it may be possible to delete files a malicious user might not otherwise have access to, such as log files.
Other
Technical Impact: Unexpected State
The product may perform invalid actions when the resource is in an unexpected state.
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