Vulnerability · Published Oct 26, 2021 · Assigned by GitHub_M
CVE-2021-41157FreeSWITCH does not authenticate SIP SUBSCRIBE requests by default
Medium 5.3
In plain English
A medium-severity improper authentication in freeswitch from signalwire. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.7% (higher than 77% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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. 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | freeswitch | 1.10.7-r0 | ALPINE-CVE-2021-41157 |
| Alpine:v3.21 | freeswitch | 1.10.7-r0 | ALPINE-CVE-2021-41157 |
| Alpine:v3.22 | freeswitch | 1.10.7-r0 | ALPINE-CVE-2021-41157 |
| Alpine:v3.23 | freeswitch | 1.10.7-r0 | ALPINE-CVE-2021-41157 |
| Alpine:v3.24 | freeswitch | 1.10.7-r0 | ALPINE-CVE-2021-41157 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| signalwire | freeswitch | < 1.10.6 |
Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
- https://github.com/signalwire/freeswitch/security/advisories/GHSA-g7xg-7c54-rmpj x_refsource_CONFIRM
- https://github.com/signalwire/freeswitch/commit/b21dd4e7f3a6f1d5f7be3ea500a319a5bc11db9e x_refsource_MISC
- https://github.com/signalwire/freeswitch/releases/tag/v1.10.6 x_refsource_MISC
- 20211026 [ES2021-08] FreeSWITCH does not authenticate SIP SUBSCRIBE requests by default mailing-list, x_refsource_FULLDISC