CVE-2020-15098

In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.20, and greater than or equal to 10.0.0 and less than 10.4.6, it has been discovered that an internal verification mechanism can be used to generate arbitrary checksums. This allows to inject arbitrary data having a valid cryptographic message authentication code (HMAC-SHA1) and can lead to various attack chains including potential privilege escalation, insecure deserialization & remote code execution. The overall severity of this vulnerability is high based on mentioned attack chains and the requirement of having a valid backend user session (authenticated). This has been patched in versions 9.5.20 and 10.4.6.

In TYPO3 CMS greater than or equal to 9.0.0 and less than 9.5.20, and greater than or equal to 10.0.0 and less than 10.4.6, it has been discovered that an internal verification mechanism can be used to generate arbitrary checksums. This allows to inject arbitrary data having a valid cryptographic message authentication code (HMAC-SHA1) and can lead to various attack chains including potential privilege escalation, insecure deserialization & remote code execution. The overall severity of this vulnerability is high based on mentioned attack chains and the requirement of having a valid backend user session (authenticated). This has been patched in versions 9.5.20 and 10.4.6.

> ### Meta > * CVSS: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C` (8.2) > * CWE-325, CWE-20, CWE-200, CWE-502 ### Problem It has been discovered that an internal verification mechanism can be used to generate arbitrary checksums. This allows to inject arbitrary data having a valid cryptographic message authentication code (HMAC-SHA1) and can lead to various attack chains as described below. * [TYPO3-CORE-SA-2020-007](https://typo3.org/security/advisory/typo3-core-sa-2020-007), [CVE-2020-15099](https://nvd.nist.gov/vuln/detail/CVE-2020-15099): Potential Privilege Escalation + the database server used for a TYPO3 installation must be accessible for an attacker (either via internet or shared hosting network) + `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C` (7.5, high) * [TYPO3-CORE-SA-2016-013](https://typo3.org/security/advisory/typo3-core-sa-2016-013), [CVE-2016-5091](https://nvd.nist.gov/vuln/detail/CVE-2016-5091): Insecure Deserialization & Remote Code Execution + an attacker must have access to at least one Extbase plugin or module action in a TYPO3 installation + `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C` (9.1, critical) The overall severity of this vulnerability is **high (8.2)** based on mentioned attack chains and the requirement of having a valid backend user session (authenticated). ### Solution Update to TYPO3 versions 9.5.20 or 10.4.6 that fix the problem described. ### Credits Thanks to TYPO3 security team member Oliver Hader who reported and fixed the issue. ### References * [TYPO3-CORE-SA-2020-008](https://typo3.org/security/advisory/typo3-core-sa-2020-008)

> ### Meta > * CVSS: `CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C` (8.2) > * CWE-325, CWE-20, CWE-200, CWE-502 ### Problem It has been discovered that an internal verification mechanism can be used to generate arbitrary checksums. This allows to inject arbitrary data having a valid cryptographic message authentication code (HMAC-SHA1) and can lead to various attack chains as described below. * [TYPO3-CORE-SA-2020-007](https://typo3.org/security/advisory/typo3-core-sa-2020-007), [CVE-2020-15099](https://nvd.nist.gov/vuln/detail/CVE-2020-15099): Potential Privilege Escalation + the database server used for a TYPO3 installation must be accessible for an attacker (either via internet or shared hosting network) + `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C` (7.5, high) * [TYPO3-CORE-SA-2016-013](https://typo3.org/security/advisory/typo3-core-sa-2016-013), [CVE-2016-5091](https://nvd.nist.gov/vuln/detail/CVE-2016-5091): Insecure Deserialization & Remote Code Execution + an attacker must have access to at least one Extbase plugin or module action in a TYPO3 installation + `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C` (9.1, critical) The overall severity of this vulnerability is **high (8.2)** based on mentioned attack chains and the requirement of having a valid backend user session (authenticated). ### Solution Update to TYPO3 versions 9.5.20 or 10.4.6 that fix the problem described. ### Credits Thanks to TYPO3 security team member Oliver Hader who reported and fixed the issue. ### References * [TYPO3-CORE-SA-2020-008](https://typo3.org/security/advisory/typo3-core-sa-2020-008)

En TYPO3 CMS versiones posteriores o igual a 9.0.0 y anteriores a 9.5.20, y versiones posteriores o igual a 10.0.0 y anteriores a 10.4.6, se ha detectado que puede ser usado un mecanismo de verificación interna para generar sumas de comprobación arbitrarias. Esto permite inyectar datos arbitrarios que tienen un código de autenticación de mensaje criptográfico válido (HMAC-SHA1) y puede conllevar a varias cadenas de ataque, incluyendo una escalada potencial de privilegios, una deserialización no segura y una ejecución de código remota. La gravedad general de esta vulnerabilidad es alta según las cadenas de ataque mencionadas y el requisito de tener una sesión de usuario del backend válida (autenticada). Esto ha sido parcheado en las versiones 9.5.20 y 10.4.6