This vulnerability in Cisco IOS Software and Cisco IOS XE Software resides in the SNMP (Simple Network Management Protocol) subsystem and can allow an authenticated, remote attacker to cause a Denial-of-Service (DoS) condition on an affected device.
Key Details of the Vulnerability:
- Cause: The issue arises due to improper error handling when parsing SNMP requests.
- Impact: If exploited successfully, the vulnerability forces the affected device to reload (crash and restart), leading to a DoS condition.
- SNMP Versions Affected:
- SNMPv1 & SNMPv2c: To exploit the flaw, the attacker must know a valid read-write or read-only SNMP community string (which acts like a password).
- SNMPv3: The attacker must have valid SNMP user credentials for the targeted system.
Exploitation Process:
- The attacker sends a specially crafted SNMP request to the vulnerable device.
- Due to improper error handling, the system fails to process the request correctly.
- This results in an unexpected reload (crash) of the device, leading to service disruption.
Potential Impact:
- Affected network devices (such as routers and switches) could become unavailable, leading to network downtime.
- Attackers with valid SNMP credentials could repeatedly exploit the flaw to disrupt network operations.
Mitigation & Protection:
- Restrict SNMP Access: Limit SNMP access to trusted IP addresses.
- Use SNMPv3 with Strong Authentication: SNMPv3 offers better security with encryption and authentication—ensure that strong credentials are used.
- Apply Cisco Patches: Cisco may have released software updates to fix this issue—updating to a patched version is highly recommended.
- Monitor SNMP Traffic: Use network monitoring tools to detect suspicious SNMP requests.