Inadequate Supply Chain Security

M3: Inadequate Supply Chain Security is a category that covers various types of flaws that allow attackers to compromise or tamper with the components or processes that are involved in the development, distribution, or maintenance of mobile applications. Supply chain is the term used to describe the network of people, organizations, activities, resources, and technologies that are involved in creating and delivering a product or service to the end user. For example, when you download and install an app from the app store, you are using the supply chain of the app developer, the app store provider, and the device manufacturer.

Inadequate supply chain security can happen when mobile applications do not verify or protect the integrity, authenticity, or quality of the components or processes that they use or rely on. For example, some common flaws are:

• Malicious code injection: Some applications use third-party libraries, frameworks, or SDKs (software development kits) to add features or functionality to their apps, but they do not check if these components are secure or trustworthy. They might contain malicious code that can execute unwanted or harmful actions on the device or the app.

• Code signing bypass: Some applications use code signing techniques to prove that their code is authentic and has not been modified by unauthorized parties. Code signing is a process of attaching a digital signature (which is like a seal of approval) to the code using a private key (which is like a secret password). However, some applications do not verify if the code signature is valid or matches the expected one. They might accept fake or forged signatures, or signatures from unknown sources.

• Repackaging attacks: Some applications are vulnerable to repackaging attacks, where an attacker downloads an original app from a legitimate source, modifies its code or resources, adds malicious code or functionality, and then uploads it to an illegitimate source (such as a fake app store or a malicious website). The repackaged app looks and behaves like the original one, but it also performs malicious actions on the device or the app.

• Update attacks: Some applications are vulnerable to update attacks, where an attacker intercepts or modifies the update process of an app and delivers a malicious update to the device. The malicious update might contain malicious code or functionality, or it might downgrade the app to a previous version that has known vulnerabilities.

These flaws can lead to serious consequences, such as data theft, data corruption, data injection, malware infection, ransomware attack, etc. Therefore, it is very important for mobile applications to implement and enforce secure supply chain security mechanisms, such as:

• Component verification: Applications should verify if the third-party components that they use are secure and trustworthy. They should only use components that are from reputable sources (such as official websites or app stores), that are up-to-date and patched for known vulnerabilities, and that have been scanned and tested for malware or malicious code.

• Code signing verification: Applications should verify if the code signature of their own code and the third-party components that they use are valid and trustworthy. They should only accept signatures that are issued by trusted authorities (such as Apple or Google), that are not expired or revoked, and that match the expected public key (which is like a public password) of the signer.

• Repackaging prevention: Applications should prevent repackaging attacks by using anti-tampering techniques to detect and prevent any modification of their code or resources. They should also use obfuscation techniques to make their code harder to read and understand by attackers. They should also monitor and report any unauthorized distribution of their apps on illegitimate sources.

• Update protection: Applications should protect their update process by using secure and encrypted communication protocols (such as HTTPS or TLS) to download updates from trusted sources (such as official websites or app stores). They should also verify if the update signature is valid and trustworthy before installing it on the device.

I hope this explanation helps you understand what M3: Inadequate Supply Chain Security is and why it is important. If you want to learn more about this category and how to prevent it, you can check out these resources:

• [M3-Inadequate Supply Chain Security | OWASP Foundation]: The official website of the OWASP Mobile Top 10 project. It contains detailed information about this category and links to other useful resources.

• [Mobile App Security: How To Secure Your Mobile App Supply Chain]: A blog post that provides an overview of the best practices for mobile app supply chain security.

• [Mobile App Security Testing | Cybrary]: A course that teaches you how to test and secure mobile applications against various security risks.