The Sony hack of late 2014 sent shock waves through Hollywood that rippled out into the rest of the world for months. The ironic hack of the dubious surveillance software company Hacking Team last summer showed no one is immune to a data breach – not even a company that specializes in breaking into systems.
After a big hack, some of the first questions asked are how the attacker got in, and whether it could have been prevented. But today we’re asking a different question: whether, once the attacker was already in the network, the breach could have been detected. And stopped.
Here’s why: Advanced attacks like the ones that hit Sony and Hacking Team are carried out by highly skilled attackers who specifically target a certain organization. Preventive measures block the great majority of threats out there, but advanced attackers know how to get around a company’s defenses. The better preventive security a company has in place, the harder it will be to get in…but the most highly skilled, highly motivated attackers will still find a way in somehow. That’s where detection comes in.
Thinking like an attacker
If an attacker does get through a company’s defensive walls, it’s critical to be able detect their presence as early as possible, to limit the damage they can do. There has been no official confirmation of when Sony’s actual breach first took place, but some reports say the company had been breached for a year before the attackers froze up Sony’s systems and began leaking volumes of juicy info about the studio’s inner workings. That’s a long time for someone to be roaming around in a network, harvesting data.
So how does one detect an attacker inside a network?
By thinking like an attacker. And thinking like an attacker requires having a thorough knowledge of how attackers work, to be able to spot their telltale traces and distinguish them from legitimate users.
Advanced or APT (Advanced Persistent Threat) attacks differ depending on the situation and the goals of the attacker, but in general their attacks tend to follow a pattern. Once they’ve chosen a target company and performed reconnaissance to find out more about the company and how to best compromise it, their attacks generally cover the following phases:
1. Gain a foothold. The first step is to infect a machine within the organization. This is typically done by exploiting software vulnerabilities on servers or endpoints, or by using social engineering tactics such as phishing, spear-phishing, watering holes, or man-in-the-middle attacks.
2. Achieve persistence. The initial step must also perform some action that lets the attacker access the system later at will. This means a persistent component that creates a backdoor the attacker can re-enter through later.
3. Perform network reconnaissance. Gather information about the initial compromised system and the whole network to figure out where and how to advance in the network.
4. Lateral movement. Gain access to further systems as needed, depending on what the goal of the attack is.
Steps 2-4 are then repeated as needed to gain access to the target data or system.
5. Collect target data. Identify and collect files, credentials, emails, and other forms of intercepted communications.
6. Exfiltrate target data. Copy data to the attackers via network.
Steps 5 and 6 can also happen in small increments over time. In some cases these steps are augmented with sabotaging data or systems.
7. Cover tracks. Evidence of what was done and how it was done is easily erased by deleting and modifying logs and file access times. This can happen throughout the attack, not just at the end.
For each phase, there are various tactics, techniques and procedures attackers use to accomplish the task as covertly as possible. Combined with an awareness and visibility of what is happening throughout the network, knowledge of these tools and techniques is what will enable companies to detect attackers in their networks and stop them in their tracks.
Following the signs
Sony may have been breached for a year, but signs of the attack were there all along. Perhaps these signs just weren’t being watched for – or perhaps they were missed.
The attackers tried to cover their tracks (step 7) with two specific tools that forged logs and file access and creation times – tools that could have been detected as being suspicious. These tools were used throughout the attack, not just at the end, so detection would have happened well before all the damage was done, saving Sony and its executives much embarrassment, difficult PR, lost productivity, and untold millions of dollars.
In the case of Hacking Team, the hacker known as Phineas Fisher used a network scanner called nmap, a common network scanning tool, to gather information about the organization’s internal network and figure out how to advance the attack (step 3). Nmap activity on a company internal network should be flagged as a suspicious activity. For moving inside the network, step 4, he used methods based on the built-in Windows management framework, PowerShell, and the well-known tool psexec from SysInternals. These techniques could also potentially have been picked up on from the way they were used that would differ from a legitimate user.
These are just a few examples of how a knowledge of how attackers work can be used to detect and stop them. In practice, F-Secure does this with a new service we’ve just launched called Rapid Detection Service. The service uses a combination of human and machine intelligence to monitor what’s going on inside a company network and detect suspicious behavior. Our promise is that once we’ve detected a breach, we’ll alert the company within 30 minutes. They’ll find out about it first from us, not from the headlines.
One F-Secure analyst sums it up nicely: “The goal is to make it impossible for an attacker to wiggle his way from an initial breach to his eventual goal.”
After all, breaches do happen. The next step, then, is to be prepared.
Photo: Getty Images
Categories