Denial of service in Python

1) Infinite loop

EUVDB-ID: #VU32881

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-20907

CWE-ID: CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop In Lib/tarfile.py in Python. A remote attacker can create a specially crafted TAR archive leading to an infinite loop when opened by tarfile.open, because _proc_pax lacks header validation.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Python: 3.8.0 - 3.8.3

External links

http://bugs.python.org/issue39017
http://github.com/python/cpython/pull/21454
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CAXHCY4V3LPAAJOBCJ26ISZ4NUXQXTUZ/
http://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VT4AF72TJ2XNIKCR4WEBR7URBJJ4YZRD/
http://usn.ubuntu.com/4428-1/

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.