CVE-2021-27363
Description
A flaw was found in the way access to sessions and handles was handled in the iSCSI driver in the Linux kernel. A local user could use this flaw to leak iSCSI transport handle kernel address or end arbitrary iSCSI connections on the system.
Mitigation
The LIBISCSI module will be auto-loaded when required, its use can be disabled by preventing the module from loading with the following instructions:
# echo "install libiscsi /bin/true" >> /etc/modprobe.d/disable-libiscsi.conf
The system will need to be restarted if the libiscsi modules are loaded. In most circumstances, the libiscsi kernel modules will be unable to be unloaded while any network interfaces are active and the protocol is in use.
If the system requires iscsi 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 | 4.4 | 4.4 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | Low | Low | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Acknowledgements
Red Hat would like to thank Adam Nichols (GRIMM) for reporting this issue.
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