Deserialization of Untrusted Data in Revive Adserver - CVE-2019-5434

Detailed vulnerability description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

An attacker could send a specifically crafted payload to the XML-RPC invocation script and trigger the unserialize() call on the "what" parameter in the "openads.spc" RPC method. Such vulnerability could be used to perform various types of attacks, e.g. exploit serialize-related PHP vulnerabilities or PHP object injection. It is possible, although unconfirmed, that the vulnerability has been used by some attackers in order to gain access to some Revive Adserver instances and deliver malware through them to third party websites. This vulnerability was addressed in version 4.2.0.

How to mitigate CVE-2019-5434

Sources

• http://packetstormsecurity.com/files/155559/Revive-Adserver-4.2-Remote-Code-Execution.html
• https://hackerone.com/reports/512076
• https://hackerone.com/reports/542670
• https://www.revive-adserver.com/security/revive-sa-2019-001/