====================================================================== Network Associates, Inc. SECURITY ADVISORY February 7, 2000 SNMPD default writable community string ====================================================================== SYNOPSIS The default configuration of SCO OpenServer 5.0.5 allows local users read/write access to SNMPD via a default writable community string. ====================================================================== VULNERABLE HOSTS This configuration has been verified on SCO OpenServer 5.0.5 and may be present in earlier versions. ====================================================================== DETAILS SNMP(S.imple N.etwork M.anagement P.rotocol) is a protocol suite used to manage information obtained from network entities such as hosts, routers, switches, hubs, etc. A management station collects the information from these various network entities via SNMP variable querys. Information events called traps can also be sent from entities to managment stations notifying the station of critical changes such as changes to interface status, packet collisions, etc. These domains of SNMP managment stations and entities are grouped togather in what are called communities. The community name (called the community string) is used as the authentication method used for information retrieval/traps. There are 2 types of community strings read(public), and write(private). A read community has privilages to retrieve variables from SNMP entities and a write community has privilages to read as well as write to entity variables. The problem lies in that the default installation of SCO OpenServer 5.0.5 has snmpd enabled with a default write(private) community string. SCO has released a security bulletin for this vulnerability, which can be found at: http://www.sco.com/security. ====================================================================== TECHNICAL DETAILS SNMPD, run on startup by SCO OpenServer 5.0.5, is configured by default with a writable(private) community string. This allows any local user full administrator access to the SNMPD facility. The potential abuses of this privelege include the ability to modify hostname, network interface state, IP forwarding and routing, state of network sockets (including the ability to terminate active TCP sessions and listening sockets) and the ARP cache. An attacker also has full read access to all SNMP facilities. ====================================================================== RESOLUTION The community string definitions can be found in /etc/snmpd.comm Remove/modify these strings and restart snmpd. Alternatively, if your site does not use SNMP, kill snmpd and remove it from system startup files. ====================================================================== CREDITS Discovery and documentation of this vulnerability was conducted by Shawn Bracken at the security labs of Network Associates. ====================================================================== ABOUT THE NETWORK ASSOCIATES SECURITY LABS The Security Labs at Network Associates hosts some of the most important research in computer security today. With over 30 security advisories published in the last 2 years, the Network Associates security auditing teams have been responsible for the discovery of many of the Internet's most serious security flaws. This advisory represents our ongoing commitment to provide critical information to the security community. For more information about the Security Labs at Network Associates, see our website at http://www.nai.com or contact us at . ====================================================================== NETWORK ASSOCIATES SECURITY LABS PGP KEY - -----BEGIN PGP PUBLIC KEY BLOCK----- Version: PGP 5.5.5 mQGiBDXGgDsRBADVOnID6BtEhKlm2cNalho28YP0JAh+J4iRUIaiWshzI0tc0KPc fvs+0xYwiqjxmeHi2sdIEPQ7S+ltA3Dlp6/DFojWBr2XB9hfWy4uiKBUHqnsKYnB Gpkh6nIx7DIwn+u0PXMXbJCG3LYf8daiPVdzC2VFtbRvJL4wZc6NLQViFQCg/9uS DuH/0NE6mO8Cu4iVrUT5Wk8D/ArOpV5T5yIuXHZO1/ZBVeHccVVvHe8wHK4D9WUs FsB8fgYLNgdFMMjtam7QQSBY/P1KKBzaFqZhkfS4WVMAFEy94NHXG+KTCPhXkZzp OPPqwWqZgfvOg0Bm20O/GhzQkB6JfFJqcfR87Ej0+fcDKrTTxAELWHGS7c9Qdn6P bfwHA/4oLNwYrtgWNkjGcG018Pu2jKT7YuP9zBTMu28IBiWdPLGL9Wle4d5cdDVx Es4iVl8FMtxlgTWCgMnBLS4nyM3pCn1HF+8Gi+IVKUXWCkqt/rtBMsrOMfrOgEIu BWnTZcTR7kcWtH7xDFNyZ47U4pElLXwATVDty/FczAJnpeht2LQyTmV0d29yayBB c3NvY2lhdGVzIFNlY3VyaXR5IExhYnMgPHNlY2xhYnNAbmFpLmNvbT6JAEsEEBEC AAsFAjXGgDsECwMCAQAKCRCheCy6j9WBEtgDAKDpYMwQZP0Ipx7X0ivnTxxJkA/W vACg4LZv0lmWqmnd7XCe4OIJ05aT6hK5Ag0ENcaAOxAIAPZCV7cIfwgXcqK61qlC 8wXo+VMROU+28W65Szgg2gGnVqMU6Y9AVfPQB8bLQ6mUrfdMZIZJ+AyDvWXpF9Sh 01D49Vlf3HZSTz09jdvOmeFXklnN/biudE/F/Ha8g8VHMGHOfMlm/xX5u/2RXscB qtNbno2gpXI61Brwv0YAWCvl9Ij9WE5J280gtJ3kkQc2azNsOA1FHQ98iLMcfFst jvbzySPAQ/ClWxiNjrtVjLhdONM0/XwXV0OjHRhs3jMhLLUq/zzhsSlAGBGNfISn CnLWhsQDGcgHKXrKlQzZlp+r0ApQmwJG0wg9ZqRdQZ+cfL2JSyIZJrqrol7DVeky CzsAAgIH/RZcJoRkhCf9O4Er+rciBNG3QqM3tek23oxGuVwqRxtGlGKuf+YaUDIA vZhARftupZYJf/+AM9pyjjsF7ON/Df5oIXXhqzrDySw47dNB3I1FG7vwAUBRfYgG NRP+zvf1nld+FgAXag1DIQteXYPtoMUJP8ZgvbELYVdZS2TapOHUv7r4rOY+UUjl U+FkQPp9KCNreaNux4NxwT3tzXl1KqqkliC8sYxvMCkJ+JO71TKGplO9dXsf3O8p 2r33+LngmLs4O7inrUlmAUKq3jmCK50J7RsZjd6PlK/0JwcjFkOZeYrxTguZzCR4 QYmo8nEHqEMSKQci0VUf9KH4lHf6xmGJAEYEGBECAAYFAjXGgDsACgkQoXgsuo/V gRK5LACgoAqLFk10kAMu6xb3ftO4+INJs14Ani+1hujlYRxYphN97c5ci8WtILNZ =L3C6 - ----