High-profile, sophisticated hackers stealing industrial secrets tend to hog the headlines but opportunistic hackers searching for routine vulnerabilities can create a world of hurt for victims, often small businesses.
Verizon’s Data Breach Investigations Report found that 79 per cent of attacks during 2011 were classified as ‘opportunistic’, where the victim is not pre-selected as a target. Victims are selected purely because they exhibit basic weaknesses that are easy to exploit. Over the last two months, the Verizon RISK team has been examining these type of attacks, looking at the source and characteristics of opportunistic attacks.
Most of the opportunistic attacks started after the miscreants scanned a few well-known ports. The most commonly scanned ports were: TCP port 3389, Microsoft’s Remote Desktop Protocol (RDP), MS SQL server (port 1433) and VNC for remote desktop, said the researchers.
Jay Jacobs, principal at Verizon’s RISK Team, said opportunistic hackers are looking for open network ports with default or easy to guess passwords. If these two conditions were met, then attackers either planted custom malware on compromised systems or used them to relay spam. the custom malware often contains key-logging software but is only occasionally derived from banking Trojan toolkits, such as Zeus.
The Verizon team also looked at the geographical location of attackers. Around 21 per cent of opportunistic attacks came from IP addresses in China. Chinese hackers prefer to go after remote access services such as RDP or MS SQL. The next most common source of attack traffic was the the US (associated with 14 per cent of attacks). IP addresses originating from the US generally prefer to target spamming/proxy services like the TDSS Proxy or McAfee’s port 6515, the researchers said.
Other common sources of attack include the Russian Federation (8 per cent) and South Korea (4 per cent).
Jacobs said in some cases, Eastern European crooks might have been scanning for victims using compromised machines in China, so Verizon's figures should only be taken as indicative rather than a precise breakdown of the actual physical location of opportunistic hackers. He said that a mix of different criminal hacking groups – from small to large and well organised – were involved in the attacks.
Most of the attacks are profit-orientated. Jacobs said that hacktivists such as Anonymous were generally interested in targeted attacks.
Opportunistic attackers use very simple techniques, looking for a single vulnerability across many hosts before moving on if they don't immediately locate a problem (97.4 per cent of IP addresses that sent packets only checked one port). Hackers of this ilk latch onto the first target that is susceptible to the single style of attack they use. Opportunistic hackers typically use automated tools to carry out these scans, which produce a huge treasure trove of information which most hackers are ill-equipped to handle.
Jacobs said defending against this type of attack is not particularly difficult, even for small businesses. Keeping unnecessary services off the internet and ensuring that strong passwords are used throughout an organisation are probably enough to keep small business safe from opportunistic attacks. Since basic security controls and practices are enough to block opportunistic hackers their victims are more likely to be small businesses, without any security policies in place.
"Opportunistic hackers are the internet equivalent of car thieves who walk through a parking lot trying car doors," Jacobs said. "Although they might appear to be mundane, the impact of these financially motivated smash and grab attacks on victims can be catastrophic." ®