CVE-2017-15102
Description
From CVE.org
The tower_probe function in drivers/usb/misc/legousbtower.c in the Linux kernel before 4.8.1 allows local users (who are physically proximate for inserting a crafted USB device) to gain privileges by leveraging a write-what-where condition that occurs after a race condition and a NULL pointer dereference.
Statement
This issue affects the versions of the Linux kernel as shipped with Red Hat Enterprise Linux 5 and 6. This has been rated as having Low security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
This issue does not affect the Linux kernel packages as shipped with Red Hat Enterprise Linux 7 and MRG-2, as this flaw was fixed in 7.4 release.
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 | 6.3 | 6.3 | N/A |
| Attack Vector | Physical | Physical | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:P/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.0/AV:P/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
Acknowledgements
Red Hat would like to thank James Patrick Evans for reporting this issue.
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