Recent investigations have uncovered a series of memory corruption vulnerabilities within the ncurses library, which is instrumental for managing terminal displays on Unix-like operating systems, including Linux and macOS. These vulnerabilities, if exploited, could allow malicious actors to execute harmful code on susceptible systems, heightening the risk for organizations utilizing these platforms.
According to a technical report published by Microsoft Threat Intelligence researchers Jonathan Bar Or, Emanuele Cozzi, and Michael Pearse, attackers could use methods such as environment variable poisoning to string together these vulnerabilities, thereby elevating privileges and executing unauthorized code within the context of targeted applications.
The vulnerabilities are tracked as CVE-2023-29491, with a CVSS score of 7.8. Addressing these issues as of April 2023, Microsoft noted its collaboration with Apple to resolve macOS-specific vulnerabilities resulting from these flaws. This partnership underscores the ongoing efforts required to bolster security in interconnected operating environments.
Environment variables, which are user-defined entities leveraged by multiple programs, can critically influence software behavior. Misconfigurations or manipulations of these variables may lead to applications executing unauthorized actions, thereby elevating cybersecurity risk pipelines. Microsoft’s investigations revealed that ncurses interacts with several key environment variables, including TERMINFO, which could be manipulated in tandem with the identified vulnerabilities for privilege escalation.
The vulnerabilities include issues such as a stack information leak, type confusion in parameterized strings, an off-by-one error, heap out-of-bounds during parsing of terminfo database files, and potential denial-of-service scenarios due to string cancellations. The researchers indicated that exploiting these vulnerabilities could allow attackers to escalate privileges, facilitating code execution within a specific application’s context. However, achieving this control typically necessitates a multi-stage attack strategy.
To successfully manipulate these vulnerabilities, an adversary might need to combine attacks, such as exploiting the stack information leak for arbitrary read capabilities alongside leveraging heap overflows for write access. This analysis reflects an understanding of tactics aligned with the MITRE ATT&CK framework, particularly regarding initial access, privilege escalation, and evasion techniques that cybercriminals might employ in these scenarios.
