#VU28793 Use of a broken or risky cryptographic algorithm in python-rsa - CVE-2020-13757

Vulnerability identifier: #VU28793

Vulnerability risk: Medium

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-13757

CWE-ID: CWE-327

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
python-rsa
Other software / Other software solutions

Vendor: sybrenstuvel

Description

The vulnerability allows a remote attacker to gain access to sensitive information on the target system.

The vulnerability exists due to the affected software does not detect ciphertext modification during decryption (prepended "0" bytes) in PKCS1_v1_5. A remote attacker gain access to sensitive information on the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

python-rsa: 4.0

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External links
https://github.com/sybrenstuvel/python-rsa/issues/146
https://github.com/sybrenstuvel/python-rsa/commit/93af6f2f89a9bf28361e67716c4240e691520f30

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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.