pppd 0.91 EAP-TLS eap.c input validation

Summaryinfo

A vulnerability identified as critical has been detected in pppd 0.91. The impacted element is an unknown function of the file eap.c of the component EAP-TLS Handler. The manipulation leads to input validation. This vulnerability is referenced as CVE-2018-11574. Remote exploitation of the attack is possible. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in pppd 0.91. It has been rated as critical. This issue affects some unknown functionality of the file eap.c of the component EAP-TLS Handler. The manipulation with an unknown input leads to a input validation vulnerability. Using CWE to declare the problem leads to CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Improper input validation together with an integer overflow in the EAP-TLS protocol implementation in PPPD may cause a crash, information disclosure, or authentication bypass. This implementation is distributed as a patch for PPPD 0.91, and includes the affected eap.c and eap-tls.c files. Configurations that use the `refuse-app` option are unaffected.

The bug was discovered 06/11/2018. The weakness was published 06/14/2018 (oss-sec). It is possible to read the advisory at openwall.com. The identification of this vulnerability is CVE-2018-11574 since 05/30/2018. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability was handled as a non-public zero-day exploit for at least 3 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 110790 (Fedora 27 : ppp (2018-b99d43ee9b)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 197295 (Ubuntu Security Notification for Ppp Vulnerability (USN-3810-1)).

Upgrading eliminates this vulnerability. A possible mitigation has been published 2 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (110790). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Name

• pppd

Version

• 0.91

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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