CVE-2017-6737: Cisco IOS and IOS XE Software SNMP Remote Code Execution Vulnerability
A vulnerability in the SNMP implementation of could allow an authenticated, remote attacker to cause a reload of the affected system or to remotely execute code. An attacker could exploit this vulnerability by sending a crafted SNMP packet to the affected device. The vulnerability is due to a buffer overflow in the affected code area. The vulnerability affects all versions of SNMP (versions 1, 2c, and 3). The attacker must know the SNMP read only community string (SNMP version 2c or earlier) or the user credentials (SNMPv3). An exploit could allow the attacker to execute arbitrary code and obtain full control of the system or to cause a reload of the affected system. Only traffic directed to the affected system can be used to exploit this vulnerability.
Other sources
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: CSCve60402.
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
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Disable SNMP on devices where SNMP is not required. (Material: 'All devices that have enabled SNMP ... should be considered vulnerable.')
SNMP enabled = false - Configuration
Explicitly exclude the affected MIBs or OIDs from SNMP access on devices that must keep SNMP enabled. (Material: 'have not explicitly excluded the affected MIBs or OIDs')
SNMP excluded_mibs_or_oids = explicitly exclude affected MIBs/OIDs - Compensating control
Restrict SNMP traffic (UDP 161/162) to trusted management IP addresses via ACLs, firewall rules, or network segmentation so only trusted hosts can send SNMP requests to the device. (Material: 'Only traffic directed to an affected system can be used to exploit these vulnerabilities.')
- Operational
Change/rotate SNMP credentials: update SNMP read-only community strings (SNMP v1/v2c) and SNMPv3 user credentials. (Material: 'The attacker must know the SNMP read only community string ... or the user credentials (SNMPv3).')
Event History
Frequently Asked Questions
What is the severity of CVE-2017-6737?
CVE-2017-6737 is rated as high severity due to potential remote code execution capabilities.
How do I fix CVE-2017-6737?
To fix CVE-2017-6737, update to the latest version of affected Cisco IOS or IOS XE software.
What products are affected by CVE-2017-6737?
CVE-2017-6737 affects multiple versions of Cisco IOS and IOS XE, ranging from 12.0 to 15.6.
Who can exploit CVE-2017-6737?
An authenticated remote attacker can exploit CVE-2017-6737 if the vulnerable SNMP service is enabled.
What are the potential consequences of CVE-2017-6737?
Exploitation of CVE-2017-6737 may allow remote code execution and disrupt services on affected devices.