@github/copilot-language-server

Problem

Digital signatures are applied to applications, packages and documents as a cryptographically secured authenticity record. Signatures are made using digital certificates, which can either be purchased from certificate authorities or be self-issued. When purchased from a certificate authority, a certificate must conform to industry standards and best practices. One such requirement is that a certificate authority must be able revoke a certificate if its misuse was reported and independently confirmed. Software users rely on the certificate revocation process to defend from malicious actors that might be controlling a certificate issued to a trusted publisher. Operating systems periodically refresh local copies of certificate revocation lists. If the signature does not include a hyperlink to the certificate revocation server, its status cannot be checked. While a commercial certificate authority is unlikely to omit this information, some policy deviations can occur in practice.

Problem

Operating systems execute application code in multiple privilege access levels. Separation of privileges is designed to protect the stability and integrity of the operating system by shielding it from issues that the user run applications may cause. However, some users may need to interact with higher privilege parts of the operating system to accomplish specific tasks. For this purpose, operating systems provide facilities that users may leverage to temporarily elevate their running privileges. Users with higher privileges can run any application with the same privilege level as their own. Attackers often try to trick privileged users into running malicious code, enabling them to infect the operating system. While the presence of code that elevates user privileges does not necessarily imply malicious intent, all of its uses in a software package should be documented and approved. Only select applications should consider using functions that can elevate user privileges. One example of acceptable use for such functions is allowing the users to install software packages and updates.

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

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

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.