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Most common email server vulnerabilities

Most common email server vulnerabilities

Common email server vulnerabilities exist because of software flaws, misconfigurations, and weak authentication practices, which expose systems to exploitation by hackers seeking unauthorized access. These vulnerabilities are a greater risk to healthcare organizations that have access to especially sensitive information that is revealed and could have detrimental consequences to patients and providers. 

For this reason alongside the use of HIPAA compliant email services providers should make themselves aware of the risks to which they are exposed.


Software flaws

Email servers and clients are inherently complex, managing thousands of connections and interactions daily.  Many organizations delay patching or upgrading their email software due to operational constraints or compatibility issues. Since email business and personal communication, it's an attractive target for attackers who continuously scan for unpatched systems or weaknesses to exploit.

When errors or weaknesses in the code are present, attackers can leverage these flaws to gain unauthorized access, manipulate email communications, or disrupt email server operations. For instance, a buffer overflow flaw allows hackers to overflow a program’s memory buffer, potentially injecting malicious code that compromises the system's security.

Similarly, input validation flaws can allow attackers to bypass security filters, injecting dangerous commands through forms or fields to access sensitive data. Unpatched software libraries or outdated email protocols can also expose servers to known vulnerabilities, creating a backdoor that hackers exploit to launch phishing attacks, spread malware, or steal confidential information.

A recent CSO article reported a vulnerability in Microsoft Outlook, known as MonikerLink (CVE 2024 21413), which allows attackers to exploit Outlook's handling of certain links, creating an opportunity for one click remote code execution attacks. By exploiting how Outlook interacts with external applications when users click on email links, attackers can trick Outlook into calling Microsoft Word to open files remotely and run potentially malicious scripts without triggering Protected View. 

See also: Can software be partially HIPAA compliant?


Misconfiguration issues

Based on an IEEE study, “Trojan horses, DOSs, intrusions, and more. These attacks can lead to user's system to leak or destroy sensitive information even crash the entire system. Most attacks exploit system's vulnerabilities or misconfigurations to gain access.”

Misconfiguration issues occur when an email server or software isn't properly set up, leaving gaps in its security that hackers can exploit. This arises from using weak security settings, not applying encryption correctly, or neglecting necessary access controls. 

In email systems, common misconfiguration problems include open relays that allow unauthorized users to send emails through the server, lack of encryption that exposes sensitive data in transit, and weak authentication requirements that make it easy for unauthorized users to access email accounts.

Hackers can exploit these vulnerabilities to gain unauthorized access, intercept confidential communications, or manipulate email traffic to distribute phishing scams or malware. For instance, if an email server doesn't enforce proper encryption, hackers can intercept and read emails that may contain sensitive information like login credentials or personal data.


Authentication weaknesses

With regards to the need for stronger  authentication in healthcare an MDPI study offered the following, The major problem in wireless healthcare environments is the vulnerability of wireless messages to access by unauthorized users, so it is desirable that strong user authentication be considered, where each user must prove their authenticity before accessing the patient’s physiological information.

Authentication weaknesses occur when systems fail to properly verify the identity of users trying to access them, creating vulnerabilities that hackers can exploit. In email systems, these weaknesses include relying on simple passwords that are easy to guess, failing to implement two factor authentication, or not properly securing account recovery processes.

Hackers often use these gaps to break into email accounts through brute force attacks, phishing schemes that trick users into revealing credentials, or password resets that exploit weak security questions. Once they gain access, they can read sensitive emails, impersonate trusted staff, or distribute phishing attacks and malware.

In healthcare emails, this is particularly dangerous because emails often contain confidential patient data, treatment plans, and billing information. If attackers gain unauthorized access to healthcare emails, they can steal patient data for identity theft or fraud, manipulate billing records, or impersonate healthcare professionals to deceive patients and staff.

See also: What is adaptive authentication?



What is a buffer overflow vulnerability?

A buffer overflow happens when too much data is written into a memory buffer, potentially allowing attackers to inject and execute malicious code.


What are open relays in email servers?

Open relays allow any external party to send emails through the server, often leading to spam or malicious emails being distributed.


How does phishing exploit email vulnerabilities?

Phishing tricks users into clicking malicious links or downloading attachments that capture login credentials or install malware.

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