Security bypass in curl (Alpine package)

1) Security bypass

EUVDB-ID: #VU5890

Risk: Medium

CVSSv3.1: 7.2 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2017-2629

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass certain security restrictions.

The vulnerability exists due to an error within TLS Certificate Status Request extension implementation (a.k.a OCSP stapling) in cURL. The problem is caused by coding error, when the affected function returns positive result even when there is none or if the server doesn't support the TLS extension in question. A remote attacker can bypass CURLOPT_SSL_VERIFYSTATUS option and make the affected system treat all requests as valid.

Successful exploitation of the vulnerability may allow an attacker to bypass implemented security controls and perform a MitM or phishing attack.

Mitigation

Install update from vendor's website.

Vulnerable software versions

curl (Alpine package): 7.52.1-r0 - 7.52.1-r1

External links

http://git.alpinelinux.org/aports/commit/?id=e57c1f8b95e9a6aecc75e9eaae6c7bf9e259adb6
http://git.alpinelinux.org/aports/commit/?id=7079fe21530ae1c8147925d8b591131b786ab2e9
http://git.alpinelinux.org/aports/commit/?id=619d9f8608068fab555a9a54e6154eb798eb5c2c
http://git.alpinelinux.org/aports/commit/?id=02d241912508f1cd6d33a41a8b8a0117385fdbbe
http://git.alpinelinux.org/aports/commit/?id=085ece4cfcbecb4f3ff3bbd6ea2696099f7ba414
http://git.alpinelinux.org/aports/commit/?id=3a9b05fb1b75a7bdcd82bc4d8020fe0b138ba0ef
http://git.alpinelinux.org/aports/commit/?id=f0e3d2c50ca204b4ddfa477de24dc480e374a651

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.