oCERT-2008-006 multiple SNMP implementations HMAC authentication spoofing
Some SNMP implementations include incomplete HMAC authentication code that allows spoofing of authenticated SNMPv3 packets.
The authentication code reads the length to be checked from sender input, this allows the sender to supply single byte HMAC code and have a 1 in 256 chance of matching the correct HMAC and authenticating, as only the first byte will be checked. The sender would need to know a valid username.
Net-SNMP <= 5.4.1, <= 5.3.2, <= 5.2.4
UCD-SNMP, all versions
eCos, all versions
Net-SNMP >= 126.96.36.199, >= 188.8.131.52, >= 184.108.40.206
eCos, patched in CVS
2008-06-05: CERT/CC reports VU#878044 to oCERT requesting joint coordination
2008-06-05: contacted affected vendors
2008-06-06: added eCos to affected packages
2008-06-09: patched net-snmp packages are released
2008-06-09: advisory release
2008-06-11: eCos patched in CVS