GEN:SID | 1:2034 |
Message | RPC ypserv maplist request TCP |
Summary | A request has been made to rpc.ypserv from an external source that should not have access to this service. This may be indicative of an intelligence gathering activity as a prelude to a more serious compromise of system resources.
service against the target host.
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Impact | Disclosure of sensitive system information to an unauthorized user. Possible denial of service.
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Detailed Information | The rpc.ypserv daemon queries information in the local NIS maps. A response to this query may divulge important information to the user performing the query. This could lead to futher exploitation of resources on the network.
In addition, a vulnerability exists in ypserv on some Linux platforms that could lead to a buffer overflow and root compromise of the target host. This is achieved by making a multitude of requests for a NIS map that does not exist.
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Affected Systems | Multiple systems running versions of ypserv prior to 2.5.
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Attack Scenarios | The attacker can craft a malicious request to rpc.ypserv such that valuable information can be returned to the attacker.
In the case of a buffer overflow, the attacker might issue a large therefore, be seen many times.
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Ease of Attack | Simple
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Corrective Action | Disallow all RPC requests from external sources and use a firewall to block access to RPC ports from outside the LAN.
Upgrade ypserv to the latest version.
Use /var/yp/securenets to list the hosts allowed to access this resource where appropriate.
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Additional References | Bugtraq: http://www.securityfocus.com/bid/6016 http://www.securityfocus.com/bid/5914
CVE: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-1232 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2000-1043 http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2000-1042
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Rule References | Cve: CAN-2002-1232
bugtraq: 5914
bugtraq: 6016
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