Lenovo discovered a firmware backdoor in RackSwitch and BladeCenter networking switch families during an internal security audit.
Security experts at Levono have spotted a firmware backdoor, tracked CVE-2017-3765, in RackSwitch and BladeCenter networking switch families during an internal security audit.
An authentication bypass affects only in RackSwitch and BladeCenter switches running ENOS (Enterprise Network Operating System), the tech giant promptly addressed it with firmware updates last week.
The Enterprise Network Operating System (ENOS) is the firmware that powers some Lenovo and IBM RackSwitch and BladeCenter switches.
The backdoor was intentionally inserted by Nortel that added it at the request of a BSSBU OEM customer.
“An authentication bypass mechanism known as “HP Backdoor” was discovered during a Lenovo security audit in the Telnet and Serial Console management interfaces, as well as the SSH and Web management interfaces under certain limited and unlikely conditions.” states the security advisory.
This bypass mechanism can be accessed when performing local authentication under specific circumstances using credentials that are unique to each switch. the exploitation of the backdoor could grant the attacker admin-level access.
Below the list of ENOS interfaces and authentication configurations affected by the issue:
- Telnet and Serial Console when performing local authentication, or a combination of RADIUS, TACACS+, or LDAP and local authentication under specific circumstances described below
- Web when performing a combination of RADIUS or TACACS+ and local authentication combined with an unlikely condition under specific circumstances described below
- SSH for certain firmware released in May 2004 through June 2004 (only) when performing a combination of RADIUS or TACACS+ and local authentication under specific circumstances described below; the vulnerable code is present in more recent firmware, but not used
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(Security Affairs –Lenovo Switches, backdoor)