[asterisk-bugs] [JIRA] (ASTERISK-21013) Security Vulnerability: sip username disclosure

[Matt Jordan (JIRA)]

     [ https://issues.asterisk.org/jira/browse/ASTERISK-21013?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Matt Jordan updated ASTERISK-21013:
-----------------------------------

    Security:     (was: Reporter, Bug Marshals, and Digium)
    
> Security Vulnerability: sip username disclosure
> -----------------------------------------------
>
>                 Key: ASTERISK-21013
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-21013
>             Project: Asterisk
>          Issue Type: Bug
>          Components: Channels/chan_sip/General
>    Affects Versions: 11.2.1
>            Reporter: Walter Doekes
>            Assignee: Kinsey Moore
>         Attachments: AST-2013-003-10.diff, AST-2013-003-11.diff, AST-2013-003-1.8.diff, ASTERISK-21013.diff, ASTERISK-21013.diff, ASTERISK-21013.diff, invite-username-disclosure-1.xml, invite-username-disclosure-1.xml, invite-username-disclosure-2.xml, invite-username-disclosure-2.xml, invite-username-disclosure-3.xml, invite-username-disclosure-3.xml, issueA21013_better_but_not_there_yet.patch, issueA21013_bogopeer_still_needs_alwaysauthreject_cleanup.patch, issueA21013_more_cleanup_more_fixes.patch, issueA21013_with_null_check.patch, register-username-disclosure-2.xml, register-username-disclosure.xml, register-username-disclosure.xml
>
>
> So.. I was trying if I could alter the SIP security framework messages to differentiate between auth failures for any UDP packet and those with a valid nonce. Those with a valid nonce would probably not have a spoofed IP, so I can use fail2ban on them with more peace of mind.
> But, then I saw the different handling of the alwaysauthreject-challenge and the "normal" challenge code. These differences can be observed by an attacker sniffing for valid usernames.
> {noformat}
> VICTIM$ sudo asterisk -nrx 'sip show peers' | head -n4
> Name/username...
> 100...
> 101...
> 102...
> VICTIM$ sudo asterisk -nrx 'core show version'
> Asterisk SVN-branch-11-r380384M
> {noformat}
> {noformat}
> ATTACKER$ sipp -m 1 -sf register-username-disclosure.xml VICTIM -s 000 -ap badpass >/dev/null 
> 000 is NOT a valid username
> ATTACKER$ sipp -m 1 -sf register-username-disclosure.xml VICTIM -s 001 -ap badpass >/dev/null 
> 001 is NOT a valid username
> ATTACKER$ sipp -m 1 -sf register-username-disclosure.xml VICTIM -s 100 -ap badpass >/dev/null 
> 100 is a valid username
> ATTACKER$ sipp -m 1 -sf register-username-disclosure.xml VICTIM -s 101 -ap badpass >/dev/null 
> 101 is a valid username
> {noformat}
> I haven't done any work on fixing the issue. But it's likely that the right fix would be to follow the normal challenge code path as much as possible.
> Regards,
> Walter Doekes
> OSSO B.V.
> (my employer wouldn't mind if OSSO B.V. is mentioned in a security bulletin if that were to be produced)

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