CVE-2023-51443: Freeswitch vulnerability (CVSS 7.5)

Description

FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to version 1.10.11, when handling DTLS-SRTP for media setup, FreeSWITCH is susceptible to Denial of Service due to a race condition in the hello handshake phase of the DTLS protocol. This attack can be done continuously, thus denying new DTLS-SRTP encrypted calls during the attack. If an attacker manages to send a ClientHello DTLS message with an invalid CipherSuite (such as `TLS_NULL_WITH_NULL_NULL`) to the port on the FreeSWITCH server that is expecting packets from the caller, a DTLS error is generated. This results in the media session being torn down, which is followed by teardown at signaling (SIP) level too. Abuse of this vulnerability may lead to a massive Denial of Service on vulnerable FreeSWITCH servers for calls that rely on DTLS-SRTP. To address this vulnerability, upgrade FreeSWITCH to 1.10.11 which includes the security fix. The solution implemented is to drop all packets from addresses that have not been validated by an ICE check.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Freeswitch< 1.10.11

Remediation

Fixed in

Freeswitch≥ 1.10.11

Patch & vendor advisories

References

http://packetstormsecurity.com/files/176311/FreeSWITCH-1.10.10-Denial-Of-Service.html
http://packetstormsecurity.com/files/176393/FreeSWITCH-Denial-Of-Service.htmlExploitThird Party AdvisoryVDB Entry
http://seclists.org/fulldisclosure/2023/Dec/29
https://github.com/signalwire/freeswitch/commit/86cbda90b84ba186e508fbc7bfae469270a97d11Patch
https://github.com/signalwire/freeswitch/security/advisories/GHSA-39gv-hq72-j6m6ExploitVendor Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2023-51443 being actively exploited?

CVE-2023-51443 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 1.49%.

How severe is CVE-2023-51443?

CVE-2023-51443 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 1.49% probability of exploitation.

Which products are affected by CVE-2023-51443?

Affected products include Freeswitch.

How do I fix CVE-2023-51443?

Upgrade affected software to a fixed version, for example Freeswitch 1.10.11 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2023-51443 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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