CVE-2021-41157 (published 2021-10-26T14:15Z)

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. By default, SIP requests of the type SUBSCRIBE are not authenticated in the affected versions of FreeSWITCH. Abuse of this security issue allows attackers to subscribe to user agent event notifications without the need to authenticate. This abuse poses privacy concerns and might lead to social engineering or similar attacks. For example, attackers may be able to monitor the status of target SIP extensions. Although this issue was fixed in version v1.10.6, installations upgraded to the fixed version of FreeSWITCH from an older version, may still be vulnerable if the configuration is not updated accordingly. Software upgrades do not update the configuration by default. SIP SUBSCRIBE messages should be authenticated by default so that FreeSWITCH administrators do not need to explicitly set the `auth-subscriptions` parameter. When following such a recommendation, a new parameter can be introduced to explicitly disable authentication.

Severity: MEDIUM
CVSS v2 base score: 5.0 (AV:N/AC:L/Au:N/C:P/I:N/A:N)
CVSS v3 base score: 5.3, MEDIUM (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N)

Weakness information:
cwe_id: CWE-306
cwe_name: Missing Authentication for Critical Function
description: The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
extended_description: 
            
            
         
         

Fix information:
repo_url: https://github.com/signalwire/freeswitch
commit_details: repo_url: https://github.com/signalwire/freeswitch
author: Donald Maxwell
author_date: 2020-09-03 12:26:04-05:00
msg: [Default-Configuration] Force sip subscription requests to require authentication.
repository: repo_url: https://github.com/signalwire/freeswitch
repo_name: signalwire/freeswitch
description: FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a versatile software implementation that runs on any commodity hardware. From a Raspberry PI to a multi-core server, FreeSWITCH can unlock the telecommunications potential of any device.
repo_language: C
owner: signalwire
file_changes: filename: internal.xml
change_type: ModificationType.MODIFY
diff: @@ -129,6 +129,8 @@
     <!-- add a ;received="<ip>:<port>" to the contact when replying to register for nat handling -->
     <!--<param name="NDLB-received-in-nat-reg-contact" value="true"/>-->
     <param name="auth-calls" value="$${internal_auth_calls}"/>
+    <!-- Force subscription requests to require authentication -->
+    <param name="auth-subscriptions" value="true"/>
     <!-- Force the user and auth-user to match. -->
     <param name="inbound-reg-force-matching-username" value="true"/>
     <!-- on authed calls, authenticate *all* the packets not just invite -->

programming_language: TeX
filename: internal.xml
change_type: ModificationType.MODIFY
diff: @@ -1,6 +1,8 @@
 <profile name="internal">
   <settings>
     <param name="auth-calls" value="true"/>
+    <!-- Force subscription requests to require authentication -->
+    <param name="auth-subscriptions" value="true"/>
     <param name="apply-nat-acl" value="nat.auto"/>
 
     <param name="debug" value="0"/>

programming_language: Shell
filename: internal.xml
change_type: ModificationType.MODIFY
diff: @@ -267,6 +267,8 @@
     <!-- add a ;received="<ip>:<port>" to the contact when replying to register for nat handling -->
     <!--<param name="NDLB-received-in-nat-reg-contact" value="true"/>-->
     <param name="auth-calls" value="$${internal_auth_calls}"/>
+    <!-- Force subscription requests to require authentication -->
+    <param name="auth-subscriptions" value="true"/>
     <!-- Force the user and auth-user to match. -->
     <param name="inbound-reg-force-matching-username" value="true"/>
     <!-- on authed calls, authenticate *all* the packets not just invite -->

programming_language: TeX
filename: internal.xml
change_type: ModificationType.MODIFY
diff: @@ -267,6 +267,8 @@
     <!-- add a ;received="<ip>:<port>" to the contact when replying to register for nat handling -->
     <!--<param name="NDLB-received-in-nat-reg-contact" value="true"/>-->
     <param name="auth-calls" value="$${internal_auth_calls}"/>
+    <!-- Force subscription requests to require authentication -->
+    <param name="auth-subscriptions" value="true"/>
     <!-- Force the user and auth-user to match. -->
     <param name="inbound-reg-force-matching-username" value="true"/>
     <!-- on authed calls, authenticate *all* the packets not just invite -->

programming_language: TeX