Multiple vulnerabilities in OpenSSL



Published: 2021-03-25
Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE ID CVE-2021-3450
CVE-2021-3449
CWE ID CWE-254
CWE-476
Exploitation vector Network
Public exploit Public exploit code for vulnerability #2 is available.
Vulnerable software
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OpenSSL
Server applications / Encryption software

Vendor OpenSSL Software Foundation

Security Advisory

1) Security features bypass

Risk: Medium

CVSSv3.1: 5.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C] [PCI]

CVE-ID: CVE-2021-3450

CWE-ID: CWE-254 - Security Features

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to an error in implementation of the X509_V_FLAG_X509_STRICT flag allows an attacker to overwrite a valid CA certificate using any non-CA certificate in the chain. As a result, a remote attacker can perform MitM attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

OpenSSL: 1.1.1h, 1.1.1i, 1.1.1j

CPE External links

https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=2a40b7bc7b94dd7de897a74571e7024f0cf0d63b
https://www.openssl.org/news/secadv/20210325.txt

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.

2) NULL pointer dereference

Risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C] [PCI]

CVE-ID: CVE-2021-3449

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: Yes

Description

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

The vulnerability exists due to a NULL pointer dereference error when processing TLSv1.2 renegotiations. A remote attacker can send a maliciously crafted renegotiation ClientHello message, which omits the signature_algorithms extension but includes a signature_algorithms_cert extension, trigger a NULL pointer dereference error and crash the server.

Mitigation

Install update from vendor's website.

Vulnerable software versions

OpenSSL: 1.1.1, 1.1.1a, 1.1.1b, 1.1.1c, 1.1.1d, 1.1.1e, 1.1.1f, 1.1.1g, 1.1.1h, 1.1.1i, 1.1.1j

CPE External links

https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=fb9fa6b51defd48157eeb207f52181f735d96148
https://www.openssl.org/news/secadv/20210325.txt

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. However, proof of concept for this vulnerability is available.



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