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
Low
PR
The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources.
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
High
C
There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data.
Integrity
High
I
There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file 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.
We would like to announce that a significant security vulnerability has been discovered in all current versions of FreePBX.
A CVE has been requested from Mitre, but has yet to be provided.
Further details as they come to hand will be available from http://community.freepbx.org/t/critical-freepbx-rce-vulnerability-all-versions/24536 which should be treated as the authoritative source of information. The CVE, when provided, will be linked from there.
There is also futher information available there about how to detect and remove any potential intrusion to your FreePBX machine.
Summary:
A remote attacker can bypass authentication and create a false FreePBX Administrator account, which will then let them perform any action on a FreePBX system as the FreePBX user (which is often 'asterisk' or 'apache').
This vulnerability is caused by the improper use of 'unserialize' in a legacy package that has been deprecated in the latest versions of FreePBX, but is still in common use.
An emergency security release has been pushed to resolve this for all supported versions (12, 2.11, and 2.10) as well as an emergency backport to 2.9, which is outside of our normal supported environment.
If you are running a version prior to 2.9, and are unable to upgrade, the patch is available below.
The fixed module versions are:
2.9: fw_ari v2.9.0.9
2.10: fw_ari v2.11.1.5
2.11: fw_ari v2.11.1.5 (not a typo, its the same module version)
In FreePBX 12 ARI is deprecated in favour of the new User Control Panel, but ARI is available as a legacy package if required, as version 12.0.5.
All versions lower than this are vulnerable and should be removed if unable to be upgraded.
Note that disabling them will NOT resolve this issue, the files must be removed or patched.
This issue was discovered by a signature verification failure on a FreePBX 12 system, and the attack appeared to be scripted. As such, this attack should be considered to be 'in the wild', and upgrades should be actioned with the utmost urgency.
FreePBX and Schmooze takes security very seriously, and treat all security issues as a critical event. We urge anyone who has discovered a security vulnerability in FreePBX, or its associated projects, to email [email protected] for an immediate response.
We also continue our recommendation that your FreePBX machines are explicitly firewalled from public access from the internet.
Additional Details:
Overall CVSS Score - 6
CVSS Base Score - 9.4
Impact Subscore - 9.2
Exploitability Subscore - 10
CVSS Temporal Score - 7.4
CVSS Environmental Score - 6
Modified Impact Subscore - 8
Link to patch:
https://github.com/FreePBX/fw_ari/commit/f294b4580ce725ca3c5e692d86e63d40cef4d836
FreePBX Security Team,
Schmooze Com Inc
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