Linux Kernel create_elf_tables() Integer Overflow Local Privilege Escalation Vulnerability (CVE-2018-14634, Mutagen Astronomer)
Executive & SecOps Summary
SECOPS ASSESSMENTLinux kernel versions 2.6.x, 3.10.x, and 4.14.x, primarily affecting Red Hat Enterprise Linux and derivative distributions.
An unprivileged local attacker can exploit this vulnerability via SUID binaries to trigger an integer overflow, achieving full root-level privilege escalation.
Apply the official vendor kernel patches immediately and reboot the system, or implement temporary SUID restrictions and SystemTap mitigations.
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Update the Linux kernel to the latest patched version using the system package manager and perform a system reboot to apply changes.
# For RHEL/CentOS systems, update the kernel package
sudo yum update -y kernel
# Reboot the system to load the patched kernel
sudo reboot
# Verify the active kernel version after reboot
uname -r2. Temporary Workaround & Hardening Configuration
If an immediate reboot is not feasible, mitigate the risk by removing the SUID bit from non-essential binaries or using SystemTap to restrict argument sizes.
# Remove SUID permission from non-essential binaries (e.g., chsh)
sudo chmod u-s /usr/bin/chsh
# Verify SUID binaries remaining on the system
find /usr/bin /usr/sbin -perm -4000 -type f3. Log Audit & IoC Verification Commands
Check if the current running kernel version falls within the vulnerable range and inspect system logs for anomalous execution attempts.
# Simple bash check for vulnerable kernel major versions
CURRENT_KERNEL=$(uname -r)
echo 'Current Kernel:' $CURRENT_KERNEL
if [[ $CURRENT_KERNEL =~ ^(2\.6|3\.10|4\.14) ]]; then
echo '[WARNING] The system is likely running a vulnerable kernel version. Patching is highly recommended.'
else
echo '[INFO] Kernel version may be patched or backported. Please verify with vendor release notes.'
fi
# Audit system logs for failed or unusual SUID executions
sudo ausearch -m syscall -S execve | grep -E 'chsh|gpasswd' | tail -n 20Block Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability, publicly known as 'Mutagen Astronomer', is an integer overflow flaw (CWE-190) located within the create_elf_tables() function of the Linux kernel's ELF binary loader. On 64-bit architectures, when a process is executed, the kernel allocates memory on the user-space stack for environment variables (envp) and command-line arguments (argv). Due to the use of signed 32-bit integers to track the size and count of these arguments, passing an extremely large volume of arguments (exceeding 2GB) triggers an integer overflow, leading to corrupted memory pointer calculations and stack wrapping.
2. Exploitation Mechanics & Attack Scenario
A local, unprivileged attacker can exploit this vulnerability by executing a SUID (Set-User-ID) binary (such as /usr/bin/chsh or /usr/bin/gpasswd) while passing millions of crafted environment variables or exceptionally long argument strings. This overflows the argument count inside create_elf_tables(), misaligning the stack pointer. The attacker can then overwrite critical memory structures of the SUID process with arbitrary payload data, hijacking the execution flow to run shellcode with root privileges.
3. Infrastructure & Business Impact
As this vulnerability is listed in the CISA KEV (Known Exploited Vulnerabilities) catalog, it represents a highly practical and actively exploited threat vector. In multi-tenant environments, shared hosting, or container hosts sharing the host kernel, a compromised low-privilege account can be leveraged to gain complete administrative control (root) over the entire operating system, leading to data exfiltration, persistent backdoors, or lateral movement across the infrastructure.
Official Vendor Advisories & References
An integer overflow flaw was found in the Linux kernel's create_elf_tables() function. An unprivileged local user with access to SUID (or otherwise privileged) binary could use this flaw to escalate their privileges on the system. Kernel versions 2.6.x, 3.10.x and 4.14.x are believed to be vulnerable.
Frequently Asked SecOps Questions (CVE-2018-14634)
FAQQ1. How critical is CVE-2018-14634 and is it actively exploited in the wild?
CVE-2018-14634 is rated CVSS 7.2 (HIGH) with a 30-day EPSS exploitation probability of 14.7%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2018-14634?
Primary impacted vendors include linux, redhat across linux_kernel. Scope summary: Linux kernel versions 2.6.x, 3.10.x, and 4.14.x (including Red Hat Enterprise Linux 7 and CentOS 7)
Q3. What temporary mitigations or workarounds exist for CVE-2018-14634 before patching?
[Mitigation] Apply the official vendor kernel patches immediately and reboot the system, or implement temporary SUID restrictions and SystemTap mitigations. Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
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