CVE-2020-13757 Python-RSA decryption of ciphertext leads to DoS
An attacker can cause excessive memory allocation or infer library usage by exploiting improper handling of leading null bytes during RSA decryption.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-13757?
CVE-2020-13757 is a high-severity vulnerability in Canonical Ubuntu Linux, published on 1 Jun 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Python-RSA before 4.1 ignores leading '\0' bytes during decryption of ciphertext. This could conceivably have a security-relevant impact, e.g., by helping an attacker to infer that an application uses Python-RSA, or if the length of accepted ciphertext affects application behavior (such as by causing excessive memory allocation).
Weakness: CWE-327
Which versions are affected by CVE-2020-13757?
3 open source packages ship an affected version, including rsa. It affects 3 products.
| Package | Affected | Fixed in |
|---|---|---|
rsa PyPI | All versions | 4.1 |
rsa PyPI | All versions | 4.1 |
rsa PyPI | All versions | 4.1 |
Linux distribution packages (23)
python-rsa SUSE:Enterprise Storage 6 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:HPE Helion OpenStack 8 | All versions | 3.4.2-3.3.1 |
python-rsa SUSE:Linux Enterprise High Performance Computing 15 SP1-ESPOS | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise High Performance Computing 15 SP1-LTSS | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Module for Basesystem 15 SP3 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Module for Package Hub 15 SP2 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Module for Package Hub 15 SP3 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Module for Public Cloud 12 | All versions | 3.1.4-12.16.1 |
python-rsa SUSE:Linux Enterprise Module for Public Cloud 15 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Server 15 SP1-BCL | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Server 15 SP1-LTSS | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Linux Enterprise Server for SAP Applications 15 SP1 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Manager Proxy 4.0 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Manager Retail Branch Server 4.0 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:Manager Server 4.0 | All versions | 3.4.2-3.4.1 |
python-rsa SUSE:OpenStack Cloud 7 | All versions | 3.1.4-12.16.1 |
python-rsa SUSE:OpenStack Cloud 8 | All versions | 3.4.2-3.3.1 |
python-rsa SUSE:OpenStack Cloud 9 | All versions | 3.4.2-4.4.1 |
python-rsa SUSE:OpenStack Cloud Crowbar 8 | All versions | 3.4.2-3.3.1 |
python-rsa SUSE:OpenStack Cloud Crowbar 9 | All versions | 3.4.2-4.4.1 |
python-rsa openSUSE:Leap 15.2 | All versions | 3.4.2-lp152.4.3.1 |
python-rsa openSUSE:Leap 15.3 | All versions | 3.4.2-3.4.1 |
Products include Canonical Ubuntu Linux, Fedoraproject Fedora, Python-Rsa Project Python-Rsa.
How do I fix CVE-2020-13757?
Upgrade rsa to 4.1 or later.
Is CVE-2020-13757 being exploited?
There is no known exploitation of CVE-2020-13757 in the wild and no public exploit code.
Other vulnerabilities in Canonical Ubuntu Linux
Sources
Also known as DEBIAN-CVE-2020-13757, GHSA-537h-rv9q-vvph, MGASA-2020-0364, PYSEC-2020-99, SUSE-SU-2021:2008-1, SUSE-SU-2021:2237-1 and 7 more.