CVE-2021-41157 FreeSWITCH does not authenticate SIP SUBSCRIBE requests by default

2021-10-2613:35:10

CWE-287

GitHub_M

www.cve.org

5.3 Medium

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

LOW

Integrity Impact

NONE

Availability Impact

NONE

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

5.9 Medium

AI Score

Confidence

High

0.001 Low

EPSS

Percentile

42.2%

JSON

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.

CNA Affected

[
  {
    "product": "freeswitch",
    "vendor": "signalwire",
    "versions": [
      {
        "status": "affected",
        "version": "< 1.10.6"
      }
    ]
  }
]