CAPEC Details
Name ICMP Address Mask Request
Likelyhood of attack Typical severity
High Low
Summary An adversary sends an ICMP Type 17 Address Mask Request to gather information about a target's networking configuration. ICMP Address Mask Requests are defined by RFC-950, "Internet Standard Subnetting Procedure." An Address Mask Request is an ICMP type 17 message that triggers a remote system to respond with a list of its related subnets, as well as its default gateway and broadcast address via an ICMP type 18 Address Mask Reply datagram. Gathering this type of information helps the adversary plan router-based attacks as well as denial-of-service attacks against the broadcast address. Many modern operating systems will not respond to ICMP type 17 messages for security reasons. Determining whether a system or router will respond to an ICMP Address Mask Request helps the adversary determine operating system or firmware version. Additionally, because these types of messages are rare, they are easily spotted by intrusion detection systems. Many ICMP scanning tools support IP spoofing to help conceal the origin of the actual request among a storm of similar ICMP messages. It is a common practice for border firewalls and gateways to be configured to block ingress ICMP type 17 and egress ICMP type 18 messages.
Prerequisites The ability to send an ICMP type 17 query (Address Mask Request) to a remote target and receive an ICMP type 18 message (ICMP Address Mask Reply) in response. Generally, modern operating systems will ignore ICMP type 17 messages, however, routers will commonly respond to this request.
Related Weaknesses
CWE ID Description
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
Related CAPECS
CAPEC ID Description
CAPEC-292 An adversary sends a probe to an IP address to determine if the host is alive. Host discovery is one of the earliest phases of network reconnaissance. The adversary usually starts with a range of IP addresses belonging to a target network and uses various methods to determine if a host is present at that IP address. Host discovery is usually referred to as 'Ping' scanning using a sonar analogy. The goal is to send a packet through to the IP address and solicit a response from the host. As such, a 'ping' can be virtually any crafted packet whatsoever, provided the adversary can identify a functional host based on its response. An attack of this nature is usually carried out with a 'ping sweep,' where a particular kind of ping is sent to a range of IP addresses.