IBM Cognos Controller 10.4.1, 10.4.2, and 11.0.0 is vulnerable to external service interaction attack, caused by improper validation of user-supplied input. A remote attacker could exploit this vulnerability to induce the application to perform server-side DNS lookups or HTTP requests to arbitrary domain names. By submitting suitable payloads, an attacker can cause the application server to attack other systems that it can interact with. IBM X-Force ID: 220903.
The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.
Since DNS names can be easily spoofed or misreported, and it may be difficult for the product to detect if a trusted DNS server has been compromised, DNS names do not constitute a valid authentication mechanism. When the product performs a reverse DNS resolution for an IP address, if an attacker controls the DNS server for that IP address, then the attacker can cause the server to return an arbitrary hostname. As a result, the attacker may be able to bypass authentication, cause the wrong hostname to be recorded in log files to hide activities, or perform other attacks. Attackers can spoof DNS names by either (1) compromising a DNS server and modifying its records (sometimes called DNS cache poisoning), or (2) having legitimate control over a DNS server associated with their IP address.