CVE Vulnerabilities

CVE-2021-3733

Uncontrolled Resource Consumption

Published: Mar 10, 2022 | Modified: Nov 21, 2024
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS 2.x
4 MEDIUM
AV:N/AC:L/Au:S/C:N/I:N/A:P
RedHat/V2
RedHat/V3
6.5 MODERATE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Ubuntu
MEDIUM

Theres a flaw in urllibs AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.

Weakness

The product does not properly control the allocation and maintenance of a limited resource.

Affected Software

Name Vendor Start Version End Version
Python Python * 3.6.14 (excluding)
Python Python 3.7.0 (including) 3.7.11 (excluding)
Python Python 3.8.0 (including) 3.8.10 (excluding)
Python Python 3.9.0 (including) 3.9.5 (excluding)
Python Python 3.10.0 (including) 3.10.0 (including)
Red Hat Enterprise Linux 8 RedHat python3-0:3.6.8-39.el8_4 *
Red Hat Enterprise Linux 8 RedHat python39:3.9-8050020210811100211.d428a79b *
Red Hat Enterprise Linux 8 RedHat python39-devel:3.9-8050020210811100211.d428a79b *
Red Hat Enterprise Linux 8 RedHat python38:3.8-8060020220120164031.5294be16 *
Red Hat Enterprise Linux 8 RedHat python38-devel:3.8-8060020220120164031.5294be16 *
Red Hat Enterprise Linux 8 RedHat python27:2.7-8060020220210185952.8cdc2268 *
Red Hat Enterprise Linux 8 RedHat python3-0:3.6.8-39.el8_4 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-python38-babel-0:2.7.0-12.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-python38-python-0:3.8.11-2.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-python38-python-cryptography-0:2.8-5.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-python38-python-jinja2-0:2.10.3-6.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-python38-python-lxml-0:4.4.1-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-python38-python-pip-0:19.3.1-2.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat rh-python38-python-urllib3-0:1.25.7-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7 RedHat python27-python-0:2.7.18-4.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat rh-python38-babel-0:2.7.0-12.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat rh-python38-python-0:3.8.11-2.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat rh-python38-python-cryptography-0:2.8-5.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat rh-python38-python-jinja2-0:2.10.3-6.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat rh-python38-python-lxml-0:4.4.1-7.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat rh-python38-python-pip-0:19.3.1-2.el7 *
Red Hat Software Collections for Red Hat Enterprise Linux 7.7 EUS RedHat rh-python38-python-urllib3-0:1.25.7-7.el7 *
Python3.10 Ubuntu hirsute *
Python3.10 Ubuntu trusty *
Python3.10 Ubuntu xenial *
Python3.4 Ubuntu esm-infra-legacy/trusty *
Python3.4 Ubuntu trusty *
Python3.4 Ubuntu trusty/esm *
Python3.5 Ubuntu esm-infra-legacy/trusty *
Python3.5 Ubuntu esm-infra/xenial *
Python3.5 Ubuntu trusty *
Python3.5 Ubuntu trusty/esm *
Python3.5 Ubuntu xenial *
Python3.6 Ubuntu bionic *
Python3.6 Ubuntu esm-infra/bionic *
Python3.6 Ubuntu trusty *
Python3.6 Ubuntu xenial *
Python3.7 Ubuntu bionic *
Python3.7 Ubuntu esm-apps/bionic *
Python3.7 Ubuntu trusty *
Python3.7 Ubuntu xenial *
Python3.8 Ubuntu bionic *
Python3.8 Ubuntu esm-apps/bionic *
Python3.8 Ubuntu esm-infra/focal *
Python3.8 Ubuntu focal *
Python3.8 Ubuntu trusty *
Python3.8 Ubuntu xenial *
Python3.9 Ubuntu esm-apps/focal *
Python3.9 Ubuntu focal *
Python3.9 Ubuntu trusty *
Python3.9 Ubuntu upstream *
Python3.9 Ubuntu xenial *

Potential Mitigations

  • Mitigation of resource exhaustion attacks requires that the target system either:

  • The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.

  • The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.

References