Vulnerability Key Information CVE: CVE-2015-8370 Affected Versions: GRUB2 versions 1.98 to 2.02 Summary: Integer underflow vulnerability in allowing authentication bypass via grub rescue shell. Impact: - Privilege Escalation: Bypass any authentication mechanism. - Information Disclosure: Modify initramfs and inject arbitrary code. - Denial of Service: Crash the system or make it unusable. --- Vulnerability Details The and functions are vulnerable due to an integer underflow error on pressing backspace, which can result in overwriting memory mistakenly. --- Exploit (Proof of Concept) Repeatedly pressing backspace 28 times and pressing leads to a GRUB rescue shell, bypassing authentication. --- Fix A patch that prevents integer underflow in the and functions was released. --- How APTs Could Use This Sensitivity An attacker could deploy a rootkit or malware by loading a customized kernel/initramfs to steal sensitive data, execute malicious commands, or gather long-term persistence. --- Discussion & Author Comments The function under this scenario could be exploited in multiple ways, impacting the system’s security. Vendors should patch quickly to mitigate risks.