GEN:SID | 1:2031 |
Message | RPC yppasswd user update UDP |
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.
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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.
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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.
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Affected Systems | All systems running the rpc.ypasswd service.
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Attack Scenarios | The attacker can make a request to update user information via rpc.ypasswd.
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Ease of Attack | Simple
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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.
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Additional References | SANS: http://www.sans.org/rr/unix/NIS.php http://www.sans.org/rr/unix/sec_solaris.php
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Rule References | bugtraq: 2763
cve: 2001-0779
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