Improper verification of cryptographic signature in phpseclib - CVE-2021-30130

Vulnerability identifier: #VU77055

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-30130

CWE-ID: CWE-347

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to improper verification of RSA PKCS#1 v1.5 signature. A remote attacker can perform MitM attack.

phpseclib
Ubuntu
php-phpseclib (Ubuntu package)

Install updates from vendor's website.

phpseclib - addressed in versions 2.0.31, 3.0.7
php-phpseclib (Ubuntu package) - addressed in versions 1.0.1-3ubuntu0.1+esm1, 1.0.9-1ubuntu0.1~esm1, 1.0.18-2ubuntu0.1~esm1, 1.0.20-1ubuntu0.1~esm1, 2.0.1-1ubuntu0.1~esm2, 2.0.9-1ubuntu0.1~esm2, 2.0.23-2ubuntu0.1~esm2, 2.0.36-1ubuntu0.1~esm2, 3.0.13-1ubuntu0.1~esm1

• https://github.com/phpseclib/phpseclib/releases/tag/2.0.31
• https://github.com/phpseclib/phpseclib/pull/1635
• https://github.com/phpseclib/phpseclib/releases/tag/3.0.7
• https://lists.debian.org/debian-lts-announce/2022/11/msg00024.html
• https://lists.debian.org/debian-lts-announce/2022/11/msg00025.html
• https://github.com/phpseclib/phpseclib/security/advisories/GHSA-8p5q-f4jq-7rr3

• MitM attack in phpseclib
• Ubuntu update for php-phpseclib