Thursday, March 10, 2011

GeoIP Irrelevance

GeoIP has traditionally served as a first pass filter for prioritizing the analysis of inbound threats. Over the last few years the value of GeoIP for this purpose has noticeably depreciated and it’s only going to get worse. It’s all relative of course; “worse” doesn’t mean useless, just less valuable in a security context.

At its heart, GeoIP is essentially a mapping between an IP address and some location on a map – and that location may be as specific as a street and postcode, or as broad as a country’s name.

It’s important to note that the various Internet authorities don’t actually administer these IP distribution maps. Unfortunately, there isn’t anything prohibiting (or forcing) IP addresses from being linked to a particular geographical location beyond the registration of netblocks (ranges of contiguous IP addresses) to various entities and where they ultimately choose to host their equipment.

The correlation between IP address and geographical location is left to various organizations (mostly commercial) that have invested in systems making use of a mix of data mining, beaconing and solicitation to obtain actual location information – and this information is bundled up and sold in various consumable formats.

The accuracy of the GeoIP information has always been “variable”. For IP’s associated with large residential ISP’s operating in Western countries – the data is pretty accurate since much of that information has actually been supplied by the subscribers themselves (one way or another – whether they meant to disclose it or not). For IP’s associated with large international organizations – the location data is more often than not meaningless – since it often only reflects the address of the organizations global headquarters rather than the IP’s being used in their various offices and data centers. I’ve found that the more obscure an organization is and the larger their netblock of assigned IP addresses, the less likely GeoIP information will be accurate.

Those artifacts of GeoIP have always been present, but why are things getting worse? There are effectively 3 key aspects as I see it:
  1. You’ve probably heard the news (repeatedly over the last 5 years) that IPv4 IP addresses are running out and just last month the last /8’s were allocated. What this means is that there’s growing pressure to optimize, divide and reassign existing netblock allocations. The result of this is that IP addresses are changing hands – between ISP, organizations, hosting facilities and even countries – at a pace faster than traditional GeoIP service providers can track accurately. This obviously has a catastrophic effect on IP reputation systems too – but I’ll address that issue in a later blog.
  2. The growth of cloud computing, on-demand service provisioning and global balancing of content delivery networks has meant that larger swathes of IP addresses are incorporated into umbrella corporate locations – typically their main data center location. Meanwhile, the organizations utilizing these services may be located anywhere around the world. For example, an organized crime syndicate in Thailand could launch a spear-phishing campaign against Cambodian businesses – sending emails from the US-based Amazon EC2 cloud, and hosting the fraud server within the UK-based ElasticHosts cloud.
  3. There are more service providers offering services that can be easily leveraged for criminal purposes and further obfuscate the true source of an attack – often intentionally (e.g. bullet-proof hosting providers and “privacy protection” services). The trend towards a federated development and provisioning of cybercrime attacks means that the GeoIP information resolves poorly to the generic hosting providers – whose services can be acquired from anywhere around the world. Often the GeoIP data is incorrect – as the service providers have altered or tampered key registration and hosting details.

That all said, GeoIP information is still an incredibly useful first-pass filter for dealing with and prioritizing threat responses.

How can organizations use GeoIP information to supplement their security response?

  1. Most businesses aren’t global and even the global ones don’t necessarily have all offices continuously communicating with all regions of the planet. Create a list of countries or regions that are generally deemed “hostile” and automatically escalate actions based upon observed attacks from that list. As unsavory as it sounds, most organizations can easily compile such a list when pressed – and many will find that simply blocking or dropping traffic to/from those countries will be greatly beneficial. For example, a US-based chain of frozen yogurt stores probably doesn’t need to browse web sites hosted in Somalia and is unlikely to want VPN access attempts initiated from Cypress.
  2. While the bad guys can certainly launch their attacks from “friendly” countries (and even locally) via purchased services or compromised hosts, a sizable percentage of threats encountered on a daily-basis for most organizations do little to hide their source. Therefore, distinguishing between portal login attempts (and failures) initiated from IP addresses based in Beijing China and Atlanta USA can be fruitful in optimizing threat responses.

Of course all bets are off for more sophisticated and targeted threats. But some work effort can be shed through using GeoIP relationship data to filter many criminal and persistent threats.

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