Cybercriminals ‘living off the land’

Cyber attackers are relying on “overdue invoice lures”, and “Living-off-the-Land” (LotL) techniques to sneak past defences, says HP in its quarterly HP Wolf Security Threat Insights report.

The report provides an update of real-world cyberattacks, helping organisations to keep up with the latest techniques of cybercriminals.

“Living-off-the-Land techniques expose the fundamental flaws of relying on detection alone,” says Patrick Schläpfer, principal threat researcher in the HP Wolf Security threat research team. “Because attackers are using legitimate tools, it’s difficult to spot threats without throwing up a lot of disruptive false positives. 

“Threat containment provides protection even when detection fails, preventing malware from exfiltrating or destroying user data or credentials, and preventing attacker persistence. This is why organisations should take a defence-in-depth approach to security, isolating and containing high-risk activities to reduce their attack surface.”

Based on data from millions of endpoints running HP Wolf Security, notable campaigns identified by HP threat researchers include:

• Attackers using open redirects to “cat-phish” users: In an advanced WikiLoader campaign, attackers exploited open redirect vulnerabilities within websites to circumvent detection. Users were directed to trustworthy sites, often through open redirect vulnerabilities in ad embeddings. They were then redirected to malicious sites – making it almost impossible for users to detect the switch.
• Living-off-the-BITS: Several campaigns abused the Windows Background Intelligent Transfer Service (BITS) – a legitimate mechanism used by programmers and system administrators to download or upload files to web servers and file shares. This LotL technique helped attackers remain undetected by using BITS to download the malicious files.
• Fake invoices leading to HTML smuggling attacks: HP identified threat actors hiding malware inside HTML files posing as delivery invoices which, once opened in a web browser, unleash a chain of events deploying open-source malware, AsyncRAT. Interestingly, the attackers paid little attention to the design of the lure, suggesting the attack was created with only a small investment of time and resources.

“Targeting companies with invoice lures is one of the oldest tricks in the book, but it can still be very effective and hence lucrative. Employees working in finance departments are used to receiving invoices via email, so they are more likely to open them. If successful, attackers can quickly monetise their access by selling it to cybercriminal brokers, or by deploying ransomware.”

By isolating threats that have evaded detection-based tools – but still allowing malware to detonate safely – HP Wolf Security has specific insight into the latest techniques used by cybercriminals. To date, HP Wolf Security customers have clicked on over 40-billion email attachments, web pages, and downloaded files with no reported breaches.

The report details how cybercriminals continue to diversify attack methods to bypass security policies and detection tools. Other findings include:

• At least 12% of email threats identified by HP Sure Click Enterprise* bypassed one or more email gateway scanners.
• The top threat vectors in Q1 were email attachments (53%), downloads from browsers (25%) and other infection vectors, such as removable storage – like USB thumb drives – and file shares (22).
• This quarter, at least 65% of document threats relied on an exploit to execute code, rather than macros.

This data was gathered from consenting HP Wolf Security customers from January to March 2024.