STM32Cube Debug Core

Problem

Uniform Resource Locators (URLs) are structured addresses that point to locations and assets on the internet. URLs allow software developers to build complex applications that exchange data with servers that can be hosted in multiple geographical regions. URLs can commonly be found embedded in documentation, configuration files, source code and compiled binaries. One or more embedded URLs were discovered to link to raw files hosted on GitHub. Attackers often abuse popular web services to host malicious payloads. Since code-sharing services URLs are typically allowed by security solutions, using them for payload delivery increases the odds that the malicious code will reach the user. While the presence of code-sharing service locations does not imply malicious intent, all of their uses in a software package should be documented and approved. An increasing number of software supply chain attacks in the open source space leverages the GitHub service to deliver malicious payloads.

Problem

Software license is a legal instrument that governs the use and distribution of software source code and its binary representation. Software publishers have the freedom to choose any commonly used or purposefully written license to publish their work under. While some licenses are liberal and allow almost any kind of distribution, with or without code modification, other licenses are more restrictive and impose rules for their inclusion in other software projects. Some software licenses place restrictions on software distribution of the code they apply to. These restrictions may extend to the services built upon the code licensed under such restrictive licenses. Some restrictive licenses explicitly state that the licensee may not provide the software to third parties as a hosted or managed service, where the service provides users with access to any substantial set of the features or functionality of the licensed software. When building commercial applications, this is typically undesirable. Therefore, the inclusion of any code that may impose limits on software distribution is commonly avoided or even prohibited by the organization policy.

Problem

Security Development Lifecycle (SDL) is a group of enhanced compile-time checks that report common coding mistakes as errors, preventing them from reaching production. These checks minimize the number of security issues by enforcing strict memory access checks. They also prevent the use of hard-to-secure string and memory manipulation functions. To prove the binary has been compiled with these checks enabled, the compiler emits a special debug object. Removing the debug table eliminates this proof. Therefore, this check only applies to binaries that still have their debug tables.

Problem

Presence of code relocations indicates that the code segment might temporarily, at one point, become both writable and executable. That violates security policies adopted by most modern Linux distributions. During the brief period in which the code segment is both writable and executable, the attacker may be able to overwrite the code with a malicious program.

Problem

Buffer overrun protection on Linux is achieved in two ways. The most common solution is to use the stack canary (also called cookie). The stack canary is a special value written onto the stack that allows the operating system to detect and terminate the program if a stack overrun occurs. In most cases, compilers will apply the stack canary conservatively in order to avoid a negative performance impact. Therefore, stack canaries are often used together with another stack overrun mitigation - fortified functions. Fortified functions are usually wrappers around standard glibc functions (such as memcpy) which perform boundary checks either at compile time or run time to determine if a memory violation has occurred. The compiler needs additional context to generate such calls (for example, array size that needs to be known at compile time). Because of this, the compiler will virtually never substitute all viable functions with their fortified counterparts in complex programs. However, when combined with the stack canary, fortified functions provide a good measure of buffer overrun protection.