#VU77053 Infinite loop in phpseclib - CVE-2023-27560

Vulnerability identifier: #VU77053

Vulnerability risk: Medium

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

CVE-ID: CVE-2023-27560

CWE-ID: CWE-835

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
phpseclib
Web applications / Other software

Vendor: phpseclib

Description

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

The vulnerability exists due to infinite loop with composite primefields within Math/PrimeField.php. A remote attacker can consume all available system resources and cause denial of service conditions.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

phpseclib: 3.0.0 - 3.0.18

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External links
https://github.com/phpseclib/phpseclib/commit/6298d1cd55c3ffa44533bd41906caec246b60440
https://github.com/phpseclib/phpseclib/releases/tag/3.0.19

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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.