The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE Software contains multiple vulnerabilities that could allow an authenticated, remote attacker to remotely execute code on an affected system or cause an affected system to reload. An attacker could exploit these vulnerabilities by sending a crafted SNMP packet to an affected system via IPv4 or IPv6. Only traffic directed to an affected system can be used to exploit these vulnerabilities.
The vulnerabilities are due to a buffer overflow condition in the SNMP subsystem of the affected software. The vulnerabilities affect all versions of SNMP - Versions 1, 2c, and 3. To exploit these vulnerabilities via SNMP Version 2c or earlier, the attacker must know the SNMP read-only community string for the affected system. To exploit these vulnerabilities via SNMP Version 3, the attacker must have user credentials for the affected system. A successful exploit could allow the attacker to execute arbitrary code and obtain full control of the affected system or cause the affected system to reload.
Customers are advised to apply the workaround as contained in the Workarounds section below. Fixed software information is available via the Cisco IOS Software Checker. All devices that have enabled SNMP and have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable.
Organizations should prioritize patching immediately.
Vulnerability Details
CVE-2017-6736 is classified as a high-severity vulnerability with a CVSS score of 8.8. This vulnerability allows an authenticated remote attacker to execute arbitrary code or cause a system reload. The affected products include Cisco IOS and IOS XE software versions 12.0 to 12.4 and 15.0 to 15.6, as well as IOS XE versions 2.2 to 3.17.
The publication date for this vulnerability was July 17, 2017, and it falls under the CWE classification CWE-119.
Technical Analysis
The root cause of CVE-2017-6736 is a buffer overflow condition in the SNMP subsystem, which could be exploited over the network. The attack complexity is low, and the attacker requires low privileges. User interaction is not required to exploit this vulnerability.
Successful exploitation could lead to high confidentiality, integrity, and availability impacts, as the attacker could gain full control of the affected system.
Risk & Impact Analysis
Risk to organizations includes potential unauthorized access and control over critical network infrastructure. The blast radius is significant given that SNMP is widely used for network management. Timely patching is essential to mitigate the risks associated with this vulnerability.
Organizations should address this vulnerability in their priority patch cycle.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | Yes |
Public PoC | Yes |
Actively Exploited | Yes |
Ransomware Use | No |
Affected Versions
All versions of Cisco IOS and IOS XE prior to the vendor patch are affected. Specifically, versions 12.0 to 12.4 and 15.0 to 15.6 of IOS, as well as versions 2.2 to 3.17 of IOS XE.
Mitigation & Remediation
Organizations should apply updates per vendor instructions to remediate this vulnerability. For more information on patching, refer to the Cisco IOS Software Checker.
If immediate patching is not feasible, consider implementing workarounds as outlined in the vendor advisory.
Detection Guidance
Monitor logs for unusual SNMP traffic patterns, especially packets with unexpected payload sizes. Behavioral anomalies in SNMP responses may also indicate potential exploitation attempts.
AppSecure Threat Intelligence Insight
The long-term significance of CVE-2017-6736 highlights the importance of secure SNMP configurations in network devices. Security teams should prioritize the implementation of robust access controls and regularly audit SNMP settings.
The vulnerability serves as a reminder of the potential risks associated with using legacy protocols in modern networks. Security practitioners should remain vigilant in monitoring and mitigating threats from known vulnerabilities.
For further reading on effective remediation strategies, organizations may explore our resources on penetration testing and associated best practices.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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