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High · 7.5 Public exploit CVE-2021-37624 EUVD-2021-24182

FreeSWITCH does not authenticate SIP MESSAGE requests, leading to spam and message spoofing

Published Oct 25, 2021 · Updated Aug 4, 2024 · Assigned by GitHub_M

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.

Affected products

VendorProductAffectedFixed
signalwire freeswitch < 1.10.7 —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Alpine v3.24 freeswitch 1.10.7-r0 —
Alpine v3.23 freeswitch 1.10.7-r0 —
Alpine v3.22 freeswitch 1.10.7-r0 —
Alpine v3.21 freeswitch 1.10.7-r0 —
Alpine v3.20 freeswitch 1.10.7-r0 —
Show 5 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Alpine v3.19 freeswitch 1.10.7-r0 —
Alpine v3.18 freeswitch 1.10.7-r0 —
Alpine v3.17 freeswitch 1.10.7-r0 —
Alpine v3.16 freeswitch 1.10.7-r0 —
Alpine v3.15 freeswitch 1.10.7-r0 —

Public exploits

Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.

Third-party code, not reviewed by us. Public PoCs are sometimes fake or contain malware. Read the code first and run it only in an isolated lab, against systems you are authorised to test.

GitHub 1 repository

  • 0xInfection/PewSWITCH ★ 30 · Nov 28, 2021

    A FreeSWITCH specific scanning and exploitation toolkit for CVE-2021-37624 and CVE-2021-41157.

Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.

References