CVE-2017-6742: 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: CSCve54313.
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 on an affected system or cause an affected system to reload.
— CISA
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Configure the device SNMP agent to explicitly exclude the affected MIBs or OIDs so SNMP requests for those MIBs/OIDs are not processed.
SNMP excluded_mibs_or_oids = explicitly exclude affected MIBs/OIDs - Configuration
Disable SNMP on devices where SNMP is not required (turn off the SNMP agent/service).
SNMP enabled = false - Compensating control
Restrict SNMP access to trusted hosts or networks (for example, via ACLs or firewall rules) so that only authorized management stations can send SNMP traffic to the device.
Event History
Frequently Asked Questions
What is the severity of CVE-2017-6742?
The severity of CVE-2017-6742 is considered critical as it allows authenticated remote attackers to execute arbitrary code on vulnerable Cisco IOS and IOS XE devices.
How do I fix CVE-2017-6742?
To fix CVE-2017-6742, upgrade the Cisco IOS or IOS XE software to a version that is not affected by this vulnerability.
Which Cisco products are affected by CVE-2017-6742?
CVE-2017-6742 affects various versions of Cisco IOS from 12.0 to 12.4 and 15.0 to 15.6, as well as IOS XE versions from 2.2 to 3.17.
What type of attack can CVE-2017-6742 facilitate?
CVE-2017-6742 can facilitate remote code execution attacks by allowing authenticated attackers to execute arbitrary code.
Is there a workaround for CVE-2017-6742 before applying a patch?
There are no specific workarounds for CVE-2017-6742, so patching is recommended as the primary means of mitigation.