#VU32141 Improper Certificate Validation in mbedtls - CVE-2017-2784

Vulnerability identifier: #VU32141

Vulnerability risk: High

CVSSv4.0: 7.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2017-2784

CWE-ID: CWE-295

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
mbedtls
Other software / Other software solutions

Vendor: tls.mbed.org

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

An exploitable free of a stack pointer vulnerability exists in the x509 certificate parsing code of ARM mbed TLS before 1.3.19, 2.x before 2.1.7, and 2.4.x before 2.4.2. A specially crafted x509 certificate, when parsed by mbed TLS library, can cause an invalid free of a stack pointer leading to a potential remote code execution. In order to exploit this vulnerability, an attacker can act as either a client or a server on a network to deliver malicious x509 certificates to vulnerable applications.

Mitigation
Install update from vendor's website.

Vulnerable software versions

mbedtls: 1.3.10 - 2.2.1

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External links
https://www.talosintelligence.com/reports/TALOS-2017-0274/
https://security.gentoo.org/glsa/201706-18
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2017-01

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.