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Client and Server Security

Updated Jan 30, 2024 ·

Client Security Issues​

Client security issues arise from vulnerabilities on the user's end, such as malware infections, outdated software, or weak authentication practices.

  • Exposed to phishing, malware, and unauthorized access
  • Compromised clients can leak sensitive data or become entry points for attacks

Applet​

An applet is a small Java program that runs inside a web browser to provide interactive content.

  • Applets were widely used but are now outdated
  • Can execute arbitrary code in the browser, leading to risks
  • Java's sandbox limits applet access to system resources
  • Security experts recommend avoiding applets due to vulnerabilities

Local Cache​

A cache is temporary storage for frequently accessed data, reducing lookup times and server load.

  • Browsers use cache to store web pages and DNS information
  • Cached data can be targeted or accessed by attackers
  • Chrome’s DNS cache can be viewed and cleared at chrome://net-internals/#dns

Cache Poisoning Attacks​

Cache poisoning involves attackers inserting malicious data into a cache.

  • DNS and web caches are common targets
  • Can lead to malicious redirects or system compromise

Mitigation:

  • Using DNSSEC and encrypted protocols
  • Clear cache regularly

Server Security Issues​

Server security issues occur when vulnerabilities on the server side are exploited, such as unpatched software, weak access controls, or improper configurations.

  • Exposed to data breaches, denial of service (DoS), and unauthorized access
  • Compromised servers can lead to loss of sensitive information
  • It can also allow full system control by attackers

Data Flow Control​

Data flow control manages the transfer of data to prevent overwhelming the network or server, ensuring stability and efficiency.

  • If data flow is too high, it can overwhelm bandwidth and degrade performance
  • Operating systems often include mechanisms to control and manage data flow

Two approaches to manage data flow:

  • Control Bandwidth

    • Limit data flow to avoid DoS attacks
    • OS controls regulate inbound/outbound traffic
    • Prevent overloads that can disrupt services

  • Monitor Sensitive Data Flow

    • Map data movement for proper monitoring
    • Apply strong security to protect sensitive info

Database Servers​

Database servers store information for retrieval, often supporting large datasets used for analytics. Data warehouses handle massive amounts of data, which makes them prime targets for attackers due to the valuable information they hold.

  • Aggregation Attack

    • Combine harmless pieces of data to reveal sensitive info
    • Piecing together of random data forms a larger sensitive picture
    • Example: Public report + staff directory + schedule → security exposure

  • Inference Attack

    • Deduce sensitive info from seemingly unrelated facts
    • Example: Correlating hospital data to identify a VIP’s health

To protect against aggregation and inference attacks:

  • Implement need-to-know access policies
  • Encrypt sensitive data, even in smaller datasets
  • Use traffic analysis to detect suspicious activity
info

Atomicity means that either the entire transaction succeeds or the DBMS rolls it back to its previous state (in other words, clicks the “undo” button).