sco.snmpd.txt

`======================================================================  
  
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 <[email protected]> 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 <[email protected]>.  
  
======================================================================  
  
NETWORK ASSOCIATES SECURITY LABS PGP KEY  
  
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- ----  
  
  
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