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| GEN:SID | 1:2032 |
| Message | RPC yppasswd user update TCP |
| Summary | The rpc.ypasswd service is used to update user information remotely. This service should not be available outside the local area network, external source. |
| Impact | This may be an intelligence gathering activity on available rpc services on a machine connected to external resources. The possibility also exists that an attacker may already have gained access to a NIS server and thus all resources connected to that host. |
| Detailed Information | A vulnerability exists in some versions of the rpc.ypasswd service that can lead to a remote root compromise of a vulnerable host. This activity may be an intelligence gathering exercise to ascertain wether or not the host is vulnerable to this attack. This activity may also indicate a possible compromise of a NIS server via a legitimate user account the attacker has previously garnered. Compromise of a master NIS server may present the attacker with easy access to all NIS resources the machine is connected to. |
| Affected Systems | All systems running the rpc.ypasswd service. |
| Attack Scenarios | The attacker can make a request to update user information via rpc.ypasswd. |
| Ease of Attack | Simple |
| Corrective Action | Disable the rpc.ypasswd daemon. Disallow all RPC requests from external sources and use a firewall to block access to RPC ports from outside the LAN. |
| Additional References | SANS: http://www.sans.org/rr/unix/NIS.php http://www.sans.org/rr/unix/sec_solaris.php |
| Rule References | bugtraq: 2763 cve: 2001-0779 |
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DID:896805
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