SNMP community string disclosure in Linksys WAP55AG

[NN Poster]

Linksys WAP55AG does not properly secure SNMP community strings. In particular, it is possible to obtain all community strings, including read/write, by querying OID 1.3.6.1.4.1.3955.2.1.13.1.2.

1.3.6.1.4.1.3955.2.1.13.1.2.1 = STRING: "public"
1.3.6.1.4.1.3955.2.1.13.1.2.2 = STRING: "private"

Verified on WAP55AG, firmware 1.07

Vendor notified 1/16/04 and 1/20/04, no response.

[Hugo van der Kooij]

On Wed, 17 Feb 2004, NN Poster wrote:

> Linksys WAP55AG does not properly secure SNMP community strings. In particular, it is possible to obtain all community strings, including read/write, by querying OID 1.3.6.1.4.1.3955.2.1.13.1.2.
>
> 1.3.6.1.4.1.3955.2.1.13.1.2.1 = STRING: "public"
> 1.3.6.1.4.1.3955.2.1.13.1.2.2 = STRING: "private"
>
> Verified on WAP55AG, firmware 1.07

But ... Can you obtain this information without a valid community string?

Hugo.

--
All email sent to me is bound to the rules described on my homepage.
hvdkooij@vanderkooij.org http://hvdkooij.xs4all.nl/
Don't meddle in the affairs of sysadmins,
for they are subtle and quick to anger.

[Nicolai van der Smagt]

Hugo wrote:


> On Wed, 17 Feb 2004, NN Poster wrote:
>
> > Linksys WAP55AG does not properly secure SNMP community strings. In particular, it is possible to obtain all community strings, including read/write, by querying OID 1.3.6.1.4.1.3955.2.1.13.1.2.
> >
> > 1.3.6.1.4.1.3955.2.1.13.1.2.1 = STRING: "public"
> > 1.3.6.1.4.1.3955.2.1.13.1.2.2 = STRING: "private"
> >
> > Verified on WAP55AG, firmware 1.07
>
> But ... Can you obtain this information without a valid community string?
>

Obviously not. However this is still a problem because with access to
only the read community string you are able to obtain the read/write
community string, so you get more than what's coming to you.

> Hugo.
--
Mvg,

Nicolai van der Smagt ~ BBned NV.
Security Officer ~ BBeyond BV.

[Robbie Stone]

Simply requiring a valid read-only community string to obtain a read-write
string is not sufficient enough protection.

It is possible to expose a read-only community string through a packet
broadcast on an unpopulated arp table on a switch, thus expose the entire unit
to attack. The owner may not even wish to update any data via SNMP, but simply
walking the table with a read-only string will allow any attacker to do so.

Can anyone confirm if the strings are writable via the read-write community
string? If an attacker was able to change the configuration and then lock-out
the remote administration capabilities it would create quite a nuisance,
especially if the access point is in a remote location.

Robbie


> On Wed, 17 Feb 2004, NN Poster wrote:
>
> > Linksys WAP55AG does not properly secure SNMP community strings. In
particular, it is possible to obtain all community strings, including
read/write, by querying OID 1.3.6.1.4.1.3955.2.1.13.1.2.
> >
> > 1.3.6.1.4.1.3955.2.1.13.1.2.1 = STRING: "public"
> > 1.3.6.1.4.1.3955.2.1.13.1.2.2 = STRING: "private"
> >
> > Verified on WAP55AG, firmware 1.07
>
> But ... Can you obtain this information without a valid community string?
>
> Hugo.
>
> --
> All email sent to me is bound to the rules described on my homepage.
> hvdkooij@vanderkooij.org http://hvdkooij.xs4all.nl/
> Don't meddle in the affairs of sysadmins,
> for they are subtle and quick to anger.
>



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