Multiple vulnerabilities in OpenSSL

1) NULL pointer dereference

EUVDB-ID: #VU50740

Risk: Medium

CVSSv3.1: 5.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-23841

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: No

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 within the X509_issuer_and_serial_hash() function when parsing the issuer field in the X509 certificate. A remote attacker can supply a specially crafted certificate, trigger a NULL pointer dereference error and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

OpenSSL: 1.0.0 - 1.1.1i

External links

http://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a51b9e1d0cf0bf8515f7201b68fb0a3482b3dc1
http://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=9b1129239f3ebb1d1c98ce9ed41d5c9476c47cb2
http://www.openssl.org/news/secadv/20210216.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) Cryptographic issues

EUVDB-ID: #VU50744

Risk: Low

CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-23839

CWE-ID: CWE-310 - Cryptographic Issues

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a MitM attack.

The vulnerability exists due to a faulty implementation of the padding check when server is configured to support SSLv2 protocol. A remote attacker can perform a MitM attack and force the server to use less secure protocols.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

OpenSSL: 1.0.2s - 1.0.2x

External links

http://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=30919ab80a478f2d81f2e9acdcca3fa4740cd547
http://www.openssl.org/news/secadv/20210216.txt
http://www.trustwave.com/en-us/resources/security-resources/security-advisories/?fid=28459

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.

3) Input validation error

EUVDB-ID: #VU50745

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-23840

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

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

The vulnerability exists due to insufficient validation of user-supplied input during EVP_CipherUpdate, EVP_EncryptUpdate and EVP_DecryptUpdate calls. A remote attacker can pass specially crafted input to the application and perform a denial of service (DoS) attack.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

OpenSSL: 1.0.0 - 1.1.1i

External links

http://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=6a51b9e1d0cf0bf8515f7201b68fb0a3482b3dc1
http://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=9b1129239f3ebb1d1c98ce9ed41d5c9476c47cb2
http://www.openssl.org/news/secadv/20210216.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.