CVE-2018-14634: Linux Kernel Integer Overflow Vulnerability

Linux kernel contains an integer overflow that can allow a local, unprivileged user who can execute an SUID or otherwise privileged binary to gain elevated privileges on the system. The issue is tracked as CVE-2018-14634 and affects the create_elf_tables() function.

How it works

The weakness is classified as CWE-190, integer overflow or wraparound. An attacker supplies input that causes an arithmetic operation inside create_elf_tables() to exceed the maximum value for the data type, producing an incorrect result that the kernel later uses when setting up the process environment.

• The overflow occurs during ELF binary loading, which is triggered whenever a user executes a binary that has the SUID bit set or that runs with other elevated privileges.
• Successful exploitation grants the attacker the privileges associated with that binary rather than their own unprivileged account.
• No public details on exact trigger values or payload construction are provided in the summary; confirm mechanics against the vendor advisory.

Am I affected? How to find it in your systems

The vulnerability exists in the Linux kernel and therefore affects any distribution or appliance that ships a vulnerable kernel version. Inventory begins with identifying all systems running Linux, including servers, workstations, containers, and embedded devices.

• Use package managers or kernel version commands to list installed kernels on each host.
• Compare the reported kernel versions and build configurations against the affected range listed in the vendor advisory; do not rely on general version assumptions.
• Look for SUID binaries that unprivileged users can execute; common locations include /usr/bin and /usr/sbin.
• Review authentication and process-creation logs for unexpected privilege changes or executions of SUID binaries by non-root accounts; specific exploitation indicators are not documented here.

How to remediate

Apply the vendor-supplied kernel update that corrects the integer handling in create_elf_tables(). This is the primary and most effective action.

• Follow the exact installation and reboot instructions in the vendor advisory for your distribution.
• After patching, audit and reduce the number of SUID binaries present on systems to limit the attack surface for this class of local-escalation flaws.
• Enforce least-privilege execution contexts for any remaining privileged binaries.

If you can't patch immediately

Apply mitigations described in the vendor advisory. Where cloud services are involved, follow applicable BOD 22-01 guidance. If mitigations cannot be implemented, discontinue use of the affected kernel until an update can be applied.

• Restrict interactive logins and limit which accounts may execute SUID binaries through file permissions or mandatory access controls.
• Monitor process-creation events and privilege transitions for anomalies until patches are deployed.
• Segment systems so that a successful local escalation on one host does not immediately grant access to additional resources.

If your data may have been exposed

Local privilege-escalation vulnerabilities that are actively exploited can lead to further compromise and data exposure. You can run a free exposure scan of your email addresses to check for presence in known breach data.