It was obvious already before that NVD really does not try very hard to actually understand or figure out the problem they grade. In this case it is quite impossible for me to understand how they could come up with this severity level. It’s like they saw “integer overflow” and figure that wow, yeah that is the most horrible flaw we can imagine, but clearly nobody at NVD engaged their brains nor looked at the “vulnerable” code or the patch that fixed the bug. Anyone that looks can see that this is not a security problem.

The vulnerability should be obvious: at some point in the boot process, the VMK transits unencrypted between the TPM and the CPU. This means that it can be captured and used to decrypt the disk.

The flaw is tracked as CVE-2023-40477 and could give remote attackers arbitrary code execution on the target system after a specially crafted RAR file is opened.

RARLAB released WinRAR version 6.23 on August 2nd, 2023, effectively addressing CVE-2023-40477.

https://www.zerodayinitiative.com/advisories/ZDI-23-1152/

MTE = Memory Tagging Extension

In mid-2022, Project Zero was provided with access to pre-production hardware implementing the ARM MTE specification. This blog post series is based on that review, and includes general conclusions about the effectiveness of MTE as implemented, specifically in the context of preventing the exploitation of memory-safety vulnerabilities.

Despite its limitations, MTE is still by far the most promising path forward for improving C/C++ software security in 2023. The ability of MTE to detect memory corruption exploitation at the first dangerous access provides a significant improvement in diagnostic and potential security effectiveness. In comparison, most other proposed approaches rely on blocking later stages in the exploitation process, for example various hardware-assisted CFI approaches which aim to block invalid control-flow transfers.

Implementation Testing

Mitigation Case Studies

The Kernel

41 in-the-wild 0-days were detected and disclosed in 2022, the second-most ever recorded since we began tracking in mid-2014, but down from the 69 detected in 2021. Although a 40% drop might seem like a clear-cut win for improving security, the reality is more complicated.