Remote code execution in cryptography package for Python

1) Integer overflow

EUVDB-ID: #VU50990

Risk: High

CVSSv3.1: 8.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-36242

CWE-ID: CWE-190 - Integer overflow

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to integer overflow when processing certain sequences of update calls to symmetrically encrypt multi-GB values. A remote attacker can pass specially crafted data to the application, trigger integer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

cryptography: 3.3 - 3.3.1

External links

http://github.com/pyca/cryptography/blob/master/CHANGELOG.rst
http://github.com/pyca/cryptography/compare/3.3.1...3.3.2
http://github.com/pyca/cryptography/issues/5615
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L7RGQLK4J5ZQFRLKCHVVG6BKZTUQMG7E/

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.