CVE-2017-6743: Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability
The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS 12.0 through 12.4 and 15.0 through 15.6 and IOS XE 2.2 through 3.17 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. All devices that have enabled SNMP and have not explicitly excluded the affected MIBs or OIDs should be considered vulnerable. Cisco Bug IDs: CSCve60376, CSCve78027.
Other sources
The Simple Network Management Protocol (SNMP) subsystem of Cisco IOS and IOS XE contains a vulnerability that could allow an authenticated, remote attacker to remotely execute code.
— CISA
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. There are workarounds that address these vulnerabilities.
— NVD
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Explicitly configure SNMP on affected Cisco IOS and IOS XE devices to exclude the affected MIBs or OIDs (i.e., add the affected MIBs/OIDs to SNMP exclusion lists) so that they are not accessible via SNMP.
SNMP subsystem (Cisco IOS / IOS XE) excluded MIBs/OIDs = exclude affected MIBs/OIDs
Event History
Frequently Asked Questions
What is the severity of CVE-2017-6743?
CVE-2017-6743 is considered a high severity vulnerability due to its potential to allow remote code execution.
How do I fix CVE-2017-6743?
You can fix CVE-2017-6743 by updating the affected Cisco IOS or IOS XE software to the latest recommended version.
Which Cisco products are affected by CVE-2017-6743?
CVE-2017-6743 affects Cisco IOS versions 12.0 to 12.4, 15.0 to 15.6, as well as IOS XE versions 2.2 to 3.17.
Who can exploit CVE-2017-6743?
An authenticated, remote attacker can exploit CVE-2017-6743 to execute arbitrary code on the affected system.
What are the potential impacts of CVE-2017-6743?
The potential impacts of CVE-2017-6743 include unauthorized remote code execution and disruption of the affected network device.