Re: Linksys 'routers', SNMP issues

From: John Duksta (jdukstaat_private)
Date: Mon Jan 07 2002 - 06:07:31 PST

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    Matthew:
    
    Are the Linksys devices accepting the SNMP packets on the
    external interface? Granted, this is a pretty bad problem
    in and of itself, but I would think not so bad if the Linksys
    device is only accepting SNMP on the internal interface.
    
    -john
    
    -- 
    John Duksta <jdukstaat_private>
    Security Engineer  - Genuity
    ---------------------------------------------------------------------------
    "Everything should be made as simple as possible but not simpler."
    - A. Einstein
    
    On Sun, 6 Jan 2002, Matthew S. Hallacy wrote:
    
    > Howdy.
    > 
    > LinkSys DSL 'routers' have some serious information leakage, and potention DDoS
    > usage. The following models have been confirmed as having this problem:
    > BEFN2PS4 (EtherFast Cable/DSL Router & Voice with 4-Port Switch)
    > BEFSR81 (EtherFast Cable/DSL Router with 8-Port Switch)
    > 
    > Querying these devices with the default community of 'public' causes them to set
    > the address that queried as their snmptrap host, dumping traffic such as the
    > following to that address:
    > 
    > Enterprise Specific Trap (1) Uptime: 2 days, 19:00:23.36, enterprises.3955.1.1.0 = "@out 192.168.1.200 ==> 24.254.60.13[110]."
    > Enterprise Specific Trap (1) Uptime: 2 days, 19:00:23.36, enterprises.3955.1.1.0 = "@out 192.168.1.200 ==> 216.120.8.23[5632]."
    > Enterprise Specific Trap (1) Uptime: 2 days, 19:00:23.36, enterprises.3955.1.1.0 = "@out 192.168.1.200 ==> 216.120.8.3[5632]."
    > Enterprise Specific Trap (1) Uptime: 2 days, 19:00:23.36, enterprises.3955.1.1.0 = "@out 192.168.1.200 ==> 216.120.8.4[5632]."
    > Enterprise Specific Trap (1) Uptime: 2 days, 19:00:23.36, enterprises.3955.1.1.0 = "@out 192.168.1.200 ==> 216.120.8.5[5632]."
    > Enterprise Specific Trap (1) Uptime: 2 days, 6:04:38.11, enterprises.3955.1.1.0 = "-->[U]Send OP:    ^ps_status_q 15049C0DFC9B03166D55EA30474D04FB 9218583272 a .."
    > Enterprise Specific Trap (1) Uptime: 2 days, 6:04:38.11, enterprises.3955.1.1.0 = "<--[U]Recv __:    ^ps_status_r.15049C0DFC9B03166D55EA30474D04FB.\"\".0.."
    > 
    > It looks like a combination of debugging information as well as traffic logging, 
    > many customers never use the configuration page, let alone change the SNMP 
    > communities. To make the matter worse, LinkSys refuses to distribute an MIB
    > for the device, which is not suprising considering the SNMP implementation
    > on the device is rather broken (it goes into a continious loop).
    > 
    > 
    > LinkSys is routing all messages regarding SNMP to /dev/null
    > 
    > 			Have a nice day.
    > 			Matthew S. Hallacy
    > 
    



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