A web shell is a malicious script that cybercriminals can use to execute arbitrary commands on a compromised server. Web shells can lead to data breaches, malware installations, and reconnaissance activities that compromise entire systems.
According to Malcolm Heath, Principal Threat Researcher at F5, “A web shell is a file that will be parsed and executed as code by a web server, which sends the results back to the originator of the web request.”
Written in common web programming languages like PHP and Java, web shells are indistinguishable from legitimate scripts to unsuspecting systems. However, their illicit nature introduces vulnerabilities that allow attackers to control the server.
How web shells work
Web shells act like secret backdoors, allowing attackers to send commands and make the server do things it’s not supposed to, like stealing data or spreading malware. Once in place, attackers can use them to spy on the server, extract files, or even install more harmful tools while appearing like normal web traffic.
Why attackers use web shells
Attackers favor web shells for several reasons. They are stealthy, blending seamlessly into normal web traffic. “Web shell traffic appears to be legitimate website traffic; a client requests a URL, and a response is returned,” Heath notes. Encrypted connections and high volumes of legitimate requests further mask malicious activity.
However, these tools are not without risks. Signature-based detection by antivirus and intrusion detection systems (IDS) can flag common web shells. Yet, as Heath warns, “Web shells can be changed and obfuscated to avoid signature-based detection,” allowing attackers to act undetected.
Defensive strategies against web shells
Detection and monitoring: Heath recommends, “Detecting suspicious web traffic, URL parameters, and directory content monitoring.” So, organizations must use tools that track unusual activity, like unauthorized commands run by a web server, that can provide early warnings.
Secure coding practices: Prevention begins with robust development standards. “Secure coding practices that aim to eliminate an attacker’s ability to upload malicious content are an absolute requirement,” he asserts.
Technical safeguards: Deploying web application firewalls and filesystem anomaly detection tools can thwart malicious activities before they escalate. More specifically, using web application firewalls and filesystem anomaly detection can block malicious activities before they cause harm. These tools act as barriers, stopping attackers in their tracks.
Administrative vigilance: Organizations must routinely inspect server directories and apply strict permissions that limit exploitable entry points. These proactive measures reduce opportunities for attackers to install web shells.
Using HIPAA compliant emails to address web shell risks
Securing patient data
HIPAA compliant email platforms, like Paubox, automatically encrypt all outgoing emails, safeguarding protected health information (PHI) even if a web shell compromises the organization’s server. These platforms block attackers exploiting web vulnerabilities from accessing or manipulating patient data.
Improving control and monitoring
HIPAA compliant email solutions equip healthcare organizations with audit trails to track when emails are sent, opened, and accessed. These monitoring tools quickly identify suspicious activity, strengthening defenses against web shells that attempt to hide in routine web traffic.
Managing risks proactively
Organizations reduce risks tied to web shell exploitation, preventing PHI exposure and the risk of breach-related fines. Additionally, it helps protect the organization’s reputation, ultimately improving patients' trust.
Integrates with existing systems
Paubox email easily integrates with Gmail and Microsoft Outlook, allowing healthcare teams to maintain secure communications without disrupting workflows. These platforms add another layer of protection against web shell attacks without complicating daily operations.
User-friendly security
Despite robust security features, HIPAA compliant email solutions remain straightforward to use. Healthcare providers communicate securely with patients, vendors, and colleagues, maintaining efficiency while mitigating web-based threats like web shells.
Read also: Federal authorities warn healthcare sector about Godzilla webshell threat
FAQs
What is HIPAA compliance?
HIPAA compliance refers to adhering to regulations outlined in the Health Insurance Portability and Accountability Act to safeguard patients’ protected health information (PHI).
Go deeper: What is HIPAA?
How does HIPAA compliance impact patient trust?
When providers are HIPAA compliant, they demonstrate a commitment to safeguarding patient privacy and improve trust in the patient-provider relationship.
What should providers do to maintain HIPAA compliance?
Providers must implement administrative, physical, and technical safeguards (like using Paubox), conduct regular risk assessments, and provide staff training to maintain HIPAA compliance.
