Talos Vulnerability Report

TALOS-2016-0141

Pidgin MXIT Contact Mood Denial of Service Vulnerability

June 21, 2016

CVE Number

CVE-2016-2373

DESCRIPTION

A denial of service vulnerability exists in the handling of the MXIT protocol in Pidgin. Specially crafted MXIT data sent via the server could potentially result in an out-of-bounds read. A malicious server or user can send an invalid mood to trigger this vulnerability.

CVSSv3 SCORE

5.9 CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

TESTED VERSIONS

Pidgin 2.10.11

PRODUCT URLs

https://www.pidgin.im/

DETAILS

In the function mxit_parse_cmd_contact in mxit/protocol.c at line 1743 contact->mood will be read from data coming from the server when parsing a contact update packet.

1743	contact->mood = atoi( rec->fields[5]->data );

At line 1759, this mood will be passed to the function mxit_update_contact():

1759			mxit_update_contact( session, contact );

This function is defined in mxit/roster.c at line 363. If mood is anything other than 0, then this value is subsequently used to as index into the mxit_moods array at line 432.

432	purple_prpl_got_user_status( session->acc, contact->username, "mood", PURPLE_MOOD_NAME, mxit_moods[contact->mood-1].mood, NULL );

This can result in an out-of-bounds read of this information, potentially resulting in a crash of the program if that memory location is not accessible.

TIMELINE

2016-04-13 - Vendor Notification
2016-06-21 - Public Disclosure

Credit

Discovered by Yves Younan of Cisco Talos.

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