CVE-2017-14179 in Apport
Summary
by MITRE
Apport before 2.13 does not properly handle crashes originating from a PID namespace allowing local users to create certain files as root which an attacker could leverage to perform a denial of service via resource exhaustion, possibly gain root privileges, or escape from containers.
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Analysis
by VulDB Data Team • 01/01/2020
The vulnerability identified as CVE-2017-14179 affects the apport crash reporting system in Ubuntu versions prior to 2.13. This flaw exists within the handling of process identifier namespace crashes and represents a critical security issue that undermines the fundamental security boundaries of Linux systems. The apport service is designed to collect crash information from applications and generate diagnostic reports, but it fails to properly validate crash data originating from PID namespaces, creating a significant attack vector for local privilege escalation and container escape scenarios.
The technical root cause of this vulnerability lies in the improper handling of crash reports that originate from processes running within PID namespaces. When a process crashes within a PID namespace, the apport system does not correctly validate the namespace context or the associated process identifiers, leading to potential privilege escalation opportunities. This flaw specifically manifests when the system attempts to create files or perform operations that should be restricted to the root user, but due to the namespace handling error, these operations can be executed with elevated privileges. The vulnerability operates at the kernel level interaction with process management and namespace handling, making it particularly dangerous in containerized environments where isolation is paramount.
The operational impact of CVE-2017-14179 extends beyond simple privilege escalation to encompass denial of service conditions and container escape capabilities. An attacker with local access to a system can exploit this vulnerability to create arbitrary files as the root user, potentially leading to resource exhaustion attacks that could bring down the system or specific services. In containerized environments, this vulnerability allows attackers to escape container boundaries and gain access to the host system, effectively nullifying the security isolation that containers are designed to provide. The attack surface is particularly concerning in cloud environments and multi-tenant systems where container isolation is critical for security.
The exploitation of this vulnerability aligns with several attack patterns documented in the MITRE ATT&CK framework, particularly those related to privilege escalation and container escape techniques. The flaw can be categorized under CWE-20: Improper Input Validation, as the system fails to properly validate crash data originating from PID namespaces. Additionally, it relates to CWE-264: Permissions, Privileges, and Access Controls, since the vulnerability allows unauthorized elevation of privileges. Organizations running affected versions of Ubuntu should immediately implement the patch released by Canonical, which properly validates PID namespace contexts when processing crash reports. The mitigation strategy involves updating to apport version 2.13 or later, along with implementing additional monitoring for suspicious file creation patterns and ensuring proper system hardening measures are in place to limit the attack surface for local users.