CVE-2021-37624

HIGH

FreeSWITCH < 1.10.7 - Unauthenticated SIP MESSAGE Spoofing and Spam

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-37624. PoCs published by 0xInfection.

AI-analyzed exploit summary PewSWITCH is a Go-based toolkit for scanning and exploiting CVE-2021-37624 and CVE-2021-41157 in FreeSWITCH. It includes functional exploit code for sending crafted MESSAGE packets and SUBSCRIBE requests to validate and exploit the vulnerabilities.

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 1.10.7, FreeSWITCH does not authenticate SIP MESSAGE requests, leading to spam and message spoofing. By default, SIP requests of the type MESSAGE (RFC 3428) are not authenticated in the affected versions of FreeSWITCH. MESSAGE requests are relayed to SIP user agents registered with the FreeSWITCH server without requiring any authentication. Although this behaviour can be changed by setting the `auth-messages` parameter to `true`, it is not the default setting. Abuse of this security issue allows attackers to send SIP MESSAGE messages to any SIP user agent that is registered with the server without requiring authentication. Additionally, since no authentication is required, chat messages can be spoofed to appear to come from trusted entities. Therefore, abuse can lead to spam and enable social engineering, phishing and similar attacks. This issue is patched in version 1.10.7. Maintainers recommend that this SIP message type is authenticated by default so that FreeSWITCH administrators do not need to be explicitly set the `auth-messages` parameter. When following such a recommendation, a new parameter can be introduced to explicitly disable authentication.

Exploits (1)

nomisec WORKING POC 29 stars
by 0xInfection · poc
https://github.com/0xInfection/PewSWITCH

PewSWITCH is a Go-based toolkit for scanning and exploiting CVE-2021-37624 and CVE-2021-41157 in FreeSWITCH. It includes functional exploit code for sending crafted MESSAGE packets and SUBSCRIBE requests to validate and exploit the vulnerabilities.

Classification
Working Poc 95%
Attack Type
Other
Complexity
Moderate
Reliability
Reliable
Target: FreeSWITCH
No auth needed
Prerequisites: Network access to FreeSWITCH SIP interface · Valid SIP extensions for targeting
devstral-2 · analyzed Feb 18, 2026 Full analysis →

References (5)

Core 5
Core References
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
http://www.openwall.com/lists/oss-security/2021/10/25/6
Exploit, Mailing List, Third Party Advisory mailing-list x_refsource_fulldisc
http://seclists.org/fulldisclosure/2021/Oct/44

Scores

CVSS v3 7.5
EPSS 0.0349
EPSS Percentile 87.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Details

CWE
CWE-287 CWE-306
Status published
Products (1)
freeswitch/freeswitch < 1.10.7
Published Oct 25, 2021
Tracked Since Feb 18, 2026