I have a client of mine that recently failed a PCI-compliance network scan by Trustwave. In a nutshell, the scan turned up a Guessable SNMP Community String
. I have all ports blocked from the WAN, and I've disabled ports 161 and 162 on the LAN. They continue to fail the test, and need to remedy this or they will start incurring fines from their credit card company. What do I do? I know what SNMP is, but I'm not an SNMP expert. Help me Experts Exchange!
udp/161 Guessable SNMP Community String
SNMP is a protocol used for remote monitoring and configuration of network devices and servers. The community string (essentially, the password) for your SNMP service was easily guessed. Although only the "read" (monitoring) string was tested, this probably means that the "write" (configuration) string is also guessable. An attacker who knows the community strings for this device will be able to monitor or reconfigure the device, potentially leading to a serious denial of service to your system or network.
At a minimum, you should change your read and write community strings to something that is hard to guess. If SNMP is not required, you should disable it. Also, SNMP (UDP/161) should not be generally accessible from the Internet.