CVE-2016-9949 in Apport
Summary
by MITRE
An issue was discovered in Apport before 2.20.4. In apport/ui.py, Apport reads the CrashDB field and it then evaluates the field as Python code if it begins with a "{". This allows remote attackers to execute arbitrary Python code.
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Analysis
by VulDB Data Team • 10/29/2024
The vulnerability identified as CVE-2016-9949 represents a critical code execution flaw within the Apport crash reporting system, a component widely used in Ubuntu and other debian-based distributions. This issue affects versions of Apport prior to 2.20.4 and stems from improper input validation in the apport/ui.py module where the system processes CrashDB field data. The flaw creates a dangerous condition where user-supplied input containing a specific format can trigger arbitrary code execution, fundamentally compromising system security. This vulnerability operates at the intersection of software configuration management and code injection, creating a pathway for attackers to gain unauthorized control over affected systems.
The technical implementation of this vulnerability occurs through a specific parsing mechanism in the Apport crash reporting framework. When the system encounters a CrashDB field that begins with an opening curly brace character, it automatically evaluates the remaining content as Python code rather than treating it as simple data. This behavior represents a classic example of insecure deserialization and dynamic code execution, where untrusted input is directly interpreted and executed without proper sanitization or validation. The flaw essentially transforms the legitimate crash reporting functionality into a potential attack vector, allowing remote adversaries to craft malicious CrashDB entries that execute arbitrary Python commands with the privileges of the Apport process.
The operational impact of CVE-2016-9949 extends beyond simple code execution, creating a comprehensive security breach that can lead to complete system compromise. Attackers exploiting this vulnerability can execute arbitrary commands on affected systems, potentially escalating privileges, accessing sensitive data, or installing malware. The remote nature of the attack means that adversaries need not have physical access to systems to exploit this flaw, making it particularly dangerous in networked environments. Systems running vulnerable versions of Apport become vulnerable to attacks that could result in data breaches, system takeover, or further propagation within network infrastructures. This vulnerability particularly affects desktop environments where Apport is actively used for crash reporting, creating a persistent threat vector for attackers targeting user workstations.
Mitigation strategies for CVE-2016-9949 primarily focus on immediate version updates and system hardening measures. The most effective solution involves upgrading to Apport version 2.20.4 or later, which includes proper input validation that prevents the evaluation of untrusted data as Python code. Organizations should implement comprehensive patch management procedures to ensure all systems are updated promptly. Additional defensive measures include network segmentation to limit access to systems running Apport, implementing monitoring for unusual crash reporting activity, and conducting regular security assessments of system components. This vulnerability aligns with CWE-94, which addresses "Improper Control of Generation of Code ('Code Injection')" and demonstrates the importance of input validation in preventing remote code execution attacks. From an ATT&CK perspective, this vulnerability maps to technique T1059.006 for "Python" command execution, representing a critical threat that requires immediate remediation to prevent exploitation in real-world scenarios.