CVE-2020-14030

An issue was discovered in Ozeki NG SMS Gateway through 4.17.6. It stores SMS messages in .NET serialized format on the filesystem. By generating (and writing to the disk) malicious .NET serialized files, an attacker can trick the product into deserializing them, resulting in arbitrary code execution.

Weakness

The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

Affected Software

Potential Mitigations

• Make fields transient to protect them from deserialization.
• An attempt to serialize and then deserialize a class containing transient fields will result in NULLs where the transient data should be. This is an excellent way to prevent time, environment-based, or sensitive variables from being carried over and used improperly.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/586.html

References

• http://www.ozeki.hu/index.php?owpn=231
• https://github.com/DrunkenShells/Disclosures/tree/master/CVE-2020-14030-RCE%20via%20.NET%20Deserialization-Ozeki%20SMS%20Gateway
• http://www.ozeki.hu/index.php?owpn=231
• https://github.com/DrunkenShells/Disclosures/tree/master/CVE-2020-14030-RCE%20via%20.NET%20Deserialization-Ozeki%20SMS%20Gateway