How to Detect Malicious Source Code

Today, modern technology has become an inseparable aspect of our lives. As a result, it’s difficult to think of a world without it. However, the advances in technology also come with risks. Especially in terms of malicious source code that threaten the health of computer systems.

In this article, we’re going to talk about malicious source code. If you understand how malicious code operates, then you can be a step ahead in containing and removing it. 

What is Malicious Source Code?

Malicious Source code is the language hostile parties “speak” to manipulate computer systems into dangerous behaviours. The writing changes or add-ons to the existing programming of computer programs, files, and infrastructure can create malicious code.

This threat is the foundational tool that carries out the vast majority of cybersecurity attacks. However, hackers probe and find weaknesses in the programming language of computers.

Then they create “phrases” known as scripts or lists of commands to abuse these vulnerabilities in these languages. These scripts can be re-used and automated via macroinstructions, or macros for short.

Hackers and other threat actors would move very slowly if they were restricted to manual methods of exploiting computer systems. Unfortunately, malicious code allows them to automate their attacks. While some codes can even replicate, spread, and cause damage on their own. Similarly, types of code may need human users to download or interact with them.

The consequences of malicious code may often lead to any of the following:

• Corruption of data
• Distributed denial-of-Service (DDoS)
• Credential theft and private info theft
• Ransom and extortion
• Nuisance and inconvenience

To help you protect yourself, let’s explore how these threats work.

How Does Malicious Code Work?

Executable + source code + build files:

Since malicious source code can also be injected into an application at a stage after development, you also need to analyze build files. For example, build files can be made to execute programs that inject malicious code at build time by the addition of a simple task, as shown in the following ant build file snippet:

<java
classname="InjectCode"
 dir="${build}"
fork="true" 
="true" maxmemory="128m"> 
<classpath>
<pathelement location="${javassist.path}"/> 
</classpath> 
</java>

Build files can also be configured to retrieve malicious dependencies from locations outside the build servers, as shown in the following snippets:

<path id="project.class.path">
<pathelement location="lib/"/>
 <pathelement path="${java.class.path}/"/>
 <pathelement path="${additional.path}"/> 
<pathelement location = "${malicious.path}"/> 
</path>

OR

<javac destdir="${build}" source="${target)" target="${target}">
<src path="${src}"/>
<classpath path="${malicious.path}" />
 </javac>

An insider can also replace existing dependencies in the build server’s local repository with malicious ones. During the build process, these malicious dependencies will use even by a benign build file and will result in malicious code will inject into every application using those dependencies. The presence of malicious code in an executable where the source code and build file both appear benign points toward this case.

How Does Malicious Code Spread?

Malicious code attackers or malware code perpetrators have a few basic intentions in spreading their venomous code throughout business applications, including:

• Steal confidential data for financial gain such as selling credit card information

• Create mischief that causes alerts and minimal damage to servers as a technical challenge

• Take revenge against a business, as by a disgruntled current or former employee

• Implement a terroristic attack such as holding the digital assets of a government agency or business for ransom

Malicious code may be used to breach systems on its own, enable secondary malicious activity, or replicate and spread itself. In any case, the original code must move from one device to another.

These threats can spread over nearly any communications channel that transmits data. Often, the vectors of spread include:

• Online networks — intranets, P2P file-sharing, public internet websites, etc.

• Social communications — email, SMS, push content, mobile messaging apps, etc.

• Wireless connectivity — Bluetooth, etc.

• Direct device interfaces — USB, etc.

Visiting infected websites or clicking on a bad email link or attachment are standard gateways for malicious code to sneak its way into your system.

However, this threat can enter from legitimate sources as well as explicitly malicious ones. Anything from public USB charging stations to exploited software update tools will misuse for these purposes.

The “packaging” of malicious code isn’t always obvious. But public data connections and any messaging service are the most important paths to watch. Downloads and URL links will often use by attackers to embed dangerous code.

How Do You Know You Have Malicious Code?

For computer users, there are several hints that malicious source code is lurking on the system:

• Performance issues for no known reason (no new software loaded).
• Frequent system crashes.
• Changes to browser home page or account passwords.
• Unfamiliar programs running in the taskbar or at system startup.

Detecting malicious software on web applications or enterprise networks is significantly more complicated. Analyzing network assets and website sources for malware or different types of malicious code involves continuous monitoring, auditing of system logs, and the use of sophisticated security tools.

How to Protect Against Malicious Attacks

Enterprise management and security teams have their work cut out for them in protecting against web application vulnerabilities and malware code.

Providing continuous protection includes a comprehensive approach to application, network, and data security that includes:

• Stress to employees the importance of never opening unexpected emails from external sources. It’s especially important to avoid opening attachments or clicking links from such sources.

• Install and update antivirus software on all computers as a first defense.

• Block pop-ups to prevent some incidents of intentional or accidental clicking on potentially harmful links.

• Use minimal permissions on web applications to limit the authority and prevent hackers from having the potential to spread malicious code to critical systems.

• Keep software updated to ensure any applicable security patches or improvements will include.

• Scan websites and code for malicious code regularly.

• Implement secure firewalls for all network traffic.

• Utilize software tools to monitor suspicious activity, especially any use of unauthorized web sites, access to bank accounts, or emails to or from unrecognized email accounts.

• Utilize secure VPN software for mobile employees who may utilize business systems from home, customer or job sites, or on public networks.

Why Offensive360

One way to avoid malicious source code in your applications is to add static analysis (also called “white-box” testing) to your software development lifecycle to review your code for the presence of malicious code. Therefore offesnsive360’s static code analysis looks at applications in non-runtime environments.

This method of security testing has distinct advantages in that it can evaluate both web as well as non-web applications. Through advanced modelling, can detect malicious code in the software’s inputs and outputs that cannot be seen through other testing methodologies.