A vulnerability in the Tool Command Language (Tcl) interpreter of Cisco IOS XE Software could allow an authenticated, local attacker to escalate from privilege level 15 to root-level privileges. This vulnerability is due to insufficient input validation of data that is passed into the Tcl interpreter. An attacker could exploit this vulnerability by loading malicious Tcl code on an affected device. A successful exploit could allow the attacker to execute arbitrary commands as root. By default, Tcl shell access requires privilege level 15.
The severity level of this vulnerability is classified as medium, with a CVSS score of 5.1. This classification is significant as it highlights the potential risk to organizations that utilize affected Cisco IOS XE devices. The real-world implications include the possibility of unauthorized access and control over critical systems.
As of now, there are no known public exploits available, but the vulnerability's characteristics indicate that it could be leveraged in targeted attacks. Therefore, organizations should prioritize patching immediately.
The urgency to address this vulnerability is underscored by its medium severity rating. Organizations should include this in their priority patch cycle to mitigate any potential risks associated with this vulnerability.
Vulnerability Details
The official CVE description states that a vulnerability in the Tool Command Language (Tcl) interpreter of Cisco IOS XE Software could allow an authenticated, local attacker to escalate from privilege level 15 to root-level privileges. This vulnerability is due to insufficient input validation of data that is passed into the Tcl interpreter.
The CVSS score assigned to this vulnerability is 5.1, indicating a medium severity level, as it poses a potential risk for unauthorized access and command execution by attackers. The affected product is Cisco's IOS XE software, which has various versions susceptible to this vulnerability.
The vulnerability was published on April 15, 2022, and classified under CWE-250 and CWE-20, indicating issues with privilege escalation and improper input validation.
Technical Analysis
The root cause of this vulnerability stems from insufficient input validation of data that is passed into the Tcl interpreter. The attack vector for this vulnerability is local, meaning that an attacker must have physical or remote access to the affected device.
The attack complexity is classified as low, and the privileges required to exploit this vulnerability are high (level 15). No user interaction is required for the exploit to be successful. The impacts on confidentiality and integrity are significant, with low confidentiality impact and high integrity impact, while availability impact is none.
Risk & Impact Analysis
Organizations using affected versions of Cisco IOS XE face real-world deployment risks due to the potential for attackers to gain root-level access. The blast radius could extend to critical systems operating with the affected software, leading to unauthorized data access and manipulation.
The urgency assessment based on the CVSS score indicates that this vulnerability should be part of an organization's immediate patching strategy. Given the potential for high integrity impact, organizations must ensure robust security measures are in place to mitigate risks.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The versions affected by this vulnerability include all versions of Cisco IOS XE prior to the vendor patch. Specific vulnerable versions include:
Cisco IOS XE 16.12.1z2, 17.2.1, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.3a, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.4.1, 17.4.1a, 17.4.1b, 17.4.1c, 17.4.2, 17.4.2a, 17.5.1, 17.5.1a, 17.5.1c.
Mitigation & Remediation
Organizations should prioritize patching immediately by updating to the latest version of Cisco IOS XE to mitigate this vulnerability. The vendor has provided adequate patch updates to address the input validation issues within the Tcl interpreter.
In the absence of an immediate patch, organizations can enhance security by implementing configuration hardening practices. This includes limiting Tcl shell access to trusted users and monitoring for any unauthorized access attempts.
For further guidance on security practices, organizations may consider leveraging resources such as penetration testing to identify potential weaknesses in their configurations.
Detection Guidance
To detect potential exploitation of this vulnerability, organizations should monitor logs for indications of unauthorized Tcl commands being executed. Behavioral anomalies that deviate from normal operational patterns should also be scrutinized.
Network signatures indicating unexpected Tcl interpreter usage can serve as an additional detection mechanism. Regular audits of system changes can help identify unauthorized modifications that may indicate exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability revolves around the importance of robust input validation in programming interfaces like Tcl. The pattern of privilege escalation vulnerabilities in critical network infrastructure highlights the necessity for security teams to implement stringent input validation controls.
Organizations should consider revisiting their security architecture to ensure that similar vulnerabilities are proactively mitigated. For strategic defensive takeaways, security teams are encouraged to adopt comprehensive testing methodologies such as penetration testing methodologies to identify and remediate input validation flaws across their applications.
Furthermore, leveraging tools and frameworks for security testing can enhance an organization's ability to pinpoint vulnerabilities before they can be exploited. Engaging in continuous security assessments will bolster defenses against similar threats in the future.
For a deeper understanding of security best practices, organizations can refer to resources on vulnerability management programs and API penetration testing strategies.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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