The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers). An example of a network attack is an attacker causing a denial of service by sending a specially crafted TCP packet across a wide area network (e.g., CVE-2004-0230).
Attack Complexity
Low
AC
The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Privileges Required
None
PR
The attacker is unauthenticated prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction
None
UI
The vulnerable system can be exploited without interaction from any human user, other than the attacker. Examples include: a remote attacker is able to send packets to a target system a locally authenticated attacker executes code to elevate privileges
Scope
Unchanged
S
An exploited vulnerability can only affect resources managed by the same security authority. In the case of a vulnerability in a virtualized environment, an exploited vulnerability in one guest instance would not affect neighboring guest instances.
Confidentiality
None
C
There is no impact on the confidentiality of the system; the attacker does not gain the ability to read any data.
Integrity
None
I
There is no impact on the integrity of the system; the attacker does not gain the ability to modify any files or information on the target system.
Availability
High
A
There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Asterisk Project Security Advisory - AST-2008-010
+------------------------------------------------------------------------+
| Product | Asterisk |
|----------------------+-------------------------------------------------|
| Summary | Asterisk IAX 'POKE' resource exhaustion |
|----------------------+-------------------------------------------------|
| Nature of Advisory | Denial of service |
|----------------------+-------------------------------------------------|
| Susceptibility | Remote Unauthenticated Sessions |
|----------------------+-------------------------------------------------|
| Severity | Critical |
|----------------------+-------------------------------------------------|
| Exploits Known | Yes |
|----------------------+-------------------------------------------------|
| Reported On | July 18, 2008 |
|----------------------+-------------------------------------------------|
| Reported By | Jeremy McNamara < jj AT nufone DOT net > |
|----------------------+-------------------------------------------------|
| Posted On | July 22, 2008 |
|----------------------+-------------------------------------------------|
| Last Updated On | July 22, 2008 |
|----------------------+-------------------------------------------------|
| Advisory Contact | Tilghman Lesher < tlesher AT digium DOT com > |
|----------------------+-------------------------------------------------|
| CVE Name | CVE-2008-3263 |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Description | By flooding an Asterisk server with IAX2 'POKE' |
| | requests, an attacker may eat up all call numbers |
| | associated with the IAX2 protocol on an Asterisk server |
| | and prevent other IAX2 calls from getting through. Due |
| | to the nature of the protocol, IAX2 POKE calls will |
| | expect an ACK packet in response to the PONG packet sent |
| | in response to the POKE. While waiting for this ACK |
| | packet, this dialog consumes an IAX2 call number, as the |
| | ACK packet must contain the same call number as was |
| | allocated and sent in the PONG. |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Resolution | The implementation has been changed to no longer allocate |
| | an IAX2 call number for POKE requests. Instead, call |
| | number 1 has been reserved for all responses to POKE |
| | requests, and ACK packets referencing call number 1 will |
| | be silently dropped. |
+------------------------------------------------------------------------+
+---------------------------------------------------------------------------------------------------------------------------------+
|Commentary|This vulnerability was reported to us without exploit code, less than two days before public release, with exploit |
| |code. Additionally, we were not informed of the public release of the exploit code and only learned this fact from a |
| |third party. We reiterate that this is irresponsible security disclosure, and we recommend that in the future, |
| |adequate time be given to fix any such vulnerability. Recommended reading: |
| |http://www.oisafety.org/guidelines/Guidelines%20for%20Security%20Vulnerability%20Reporting%20and%20Response%20V2.0.pdf|
+---------------------------------------------------------------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Affected Versions |
|------------------------------------------------------------------------|
| Product | Release | |
| | Series | |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.0.x | All versions |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.2.x | All versions prior to |
| | | 1.2.30 |
|----------------------------------+-------------+-----------------------|
| Asterisk Open Source | 1.4.x | All versions prior to |
| | | 1.4.21.2 |
|----------------------------------+-------------+-----------------------|
| Asterisk Addons | 1.2.x | Not affected |
|----------------------------------+-------------+-----------------------|
| Asterisk Addons | 1.4.x | Not affected |
|----------------------------------+-------------+-----------------------|
| Asterisk Business Edition | A.x.x | All versions |
|----------------------------------+-------------+-----------------------|
| Asterisk Business Edition | B.x.x.x | All versions prior to |
| | | B.2.5.4 |
|----------------------------------+-------------+-----------------------|
| Asterisk Business Edition | C.x.x.x | All versions prior to |
| | | C.1.10.3 |
|----------------------------------+-------------+-----------------------|
| AsteriskNOW | pre-release | All versions |
|----------------------------------+-------------+-----------------------|
| Asterisk Appliance Developer Kit | 0.x.x | All versions |
|----------------------------------+-------------+-----------------------|
| s800i (Asterisk Appliance) | 1.0.x | All versions prior to |
| | | 1.2.0.1 |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Corrected In |
|------------------------------------------------------------------------|
| Product | Release |
|---------------------------------------------+--------------------------|
| Asterisk Open Source | 1.2.30 |
|---------------------------------------------+--------------------------|
| Asterisk Open Source | 1.4.21.2 |
|---------------------------------------------+--------------------------|
| Asterisk Business Edition | B.2.5.4 |
|---------------------------------------------+--------------------------|
| Asterisk Business Edition | C.1.10.3 |
|---------------------------------------------+--------------------------|
| Asterisk Business Edition | C.2.0.3 |
|---------------------------------------------+--------------------------|
| s800i (Asterisk Appliance) | 1.2.0.1 |
+------------------------------------------------------------------------+
+----------------------------------------------------------------------------------------------------------------------------+
|Links|http://www.oisafety.org/guidelines/Guidelines%20for%20Security%20Vulnerability%20Reporting%20and%20Response%20V2.0.pdf|
|-----+----------------------------------------------------------------------------------------------------------------------|
| |http://www.securityfocus.com/bid/30321/info |
+----------------------------------------------------------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Asterisk Project Security Advisories are posted at |
| http://www.asterisk.org/security |
| |
| This document may be superseded by later versions; if so, the latest |
| version will be posted at |
| http://downloads.digium.com/pub/security/AST-2008-010.pdf and |
| http://downloads.digium.com/pub/security/AST-2008-010.html |
+------------------------------------------------------------------------+
+------------------------------------------------------------------------+
| Revision History |
|------------------------------------------------------------------------|
| Date | Editor | Revisions Made |
|-----------------+--------------------+---------------------------------|
| July 22, 2008 | Tilghman Lesher | Initial release |
|-----------------+--------------------+---------------------------------|
| July 22, 2008 | Tilghman Lesher | Revised C.1 version numbers |
+------------------------------------------------------------------------+
Asterisk Project Security Advisory - AST-2008-010
Copyright (c) 2008 Digium, Inc. All Rights Reserved.
Permission is hereby granted to distribute and publish this advisory in its
original, unaltered form.
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