HP ProCurve 7000dl Series Basic Management And Configuration Manual page 170

Controlling Management Access to the ProCurve Secure Router
Using SNMP to Manage the ProCurve Secure Router
2-46
SNMP-compliant devices typically use public as the default read-only commu-
nity and private as the default read-write community. Because many organi-
zations do not change these default settings, their managed devices and SNMP
servers are vulnerable to hackers.
In addition, SNMP v1 and v2 do not include security measures to protect the
data exchanged between the SNMP agent and the SNMP server: neither the
packets nor the community strings are encrypted, and no message integrity
measures are provided. As a result, the early versions of SNMP are vulnerable
to attacks such as:
Man-in-the-middle—An attacker can alter in-transit SNMP messages gen-
erated on behalf of an authorized user in such a way as to affect manage-
ment operations. An attacker with read-write access can infiltrate any
SNMP-managed device.
Impersonation—By assuming the identity of an user who has the appro-
priate authorizations, an attacker can gain read-write access to manage-
ment operations.
Reconnaissance—Because early implementations do not encrypt the
community string or SNMP packet information, an attacker can eavesdrop
on the exchanges between SNMP agents and an SNMP server and collect
information about the network or discover the read-write community
string.
SNMPv3 addresses the major security flaws in SNMP v1 and v2 by incorporat-
ing data authentication and encryption to protect SNMP packets:
Community string encryption—SNMPv3 requires community string
encryption in all packets, protecting against attacks.
Data integrity—SNMPv3 uses usernames and passwords to determine
who can and cannot gain the read-write access necessary to modify
information. When the user provides his or her authentication password,
the password is converted into a localized key. This key, the SNMP engine
timestamp, and the actual message are compressed into a message digest
and forwarded with the packet to provide integrity authentication. There-
fore, an unauthorized user cannot alter the message in transit.
Encryption—Along with the username and authentication password,
each user is given a privacy password, which is used to encrypt the
message packet. SNMP v3 uses encryption algorithms to encrypt the
localized key and the SNMP packet.