#VU11120 Security restrictions bypass in mbed TLS - CVE-2017-18187

Vulnerability identifier: #VU11120

Vulnerability risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-18187

CWE-ID: CWE-190

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
mbed TLS
Universal components / Libraries / Libraries used by multiple products

Vendor: ARM

Description
The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The weakness exists due to integer overflow in PSK identity parsing in the ssl_parse_client_psk_identity() function in library/ssl_srv.c. A remote attacker can trigger memory corruption and bypass bounds-check.

Mitigation
Install update from vendor's website.

Vulnerable software versions

mbed TLS: 2.1.0 - 2.1.10, 2.4.0 - 2.4.2

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External links
https://github.com/ARMmbed/mbedtls/commit/83c9f495ffe70c7dd280b41fdfd4881485a3bc28

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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.