CVE-2023-4693

An out-of-bounds read flaw was found on grub2s NTFS filesystem driver. This issue may allow a physically present attacker to present a specially crafted NTFS file system image to read arbitrary memory locations. A successful attack allows sensitive data cached in memory or EFI variable values to be leaked, presenting a high Confidentiality risk.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Name	Vendor	Start Version	End Version
Grub2	Gnu	*	2.12 (excluding)
Red Hat Enterprise Linux 8	RedHat	grub2-1:2.02-156.el8	*
Red Hat Enterprise Linux 9	RedHat	grub2-1:2.06-77.el9	*
Grub2	Ubuntu	bionic	*
Grub2	Ubuntu	lunar	*
Grub2	Ubuntu	trusty	*
Grub2	Ubuntu	upstream	*
Grub2	Ubuntu	xenial	*
Grub2-signed	Ubuntu	bionic	*
Grub2-signed	Ubuntu	devel	*
Grub2-signed	Ubuntu	esm-infra-legacy/trusty	*
Grub2-signed	Ubuntu	focal	*
Grub2-signed	Ubuntu	jammy	*
Grub2-signed	Ubuntu	lunar	*
Grub2-signed	Ubuntu	mantic	*
Grub2-signed	Ubuntu	noble	*
Grub2-signed	Ubuntu	oracular	*
Grub2-signed	Ubuntu	trusty	*
Grub2-signed	Ubuntu	trusty/esm	*
Grub2-signed	Ubuntu	xenial	*
Grub2-unsigned	Ubuntu	bionic	*
Grub2-unsigned	Ubuntu	focal	*
Grub2-unsigned	Ubuntu	jammy	*
Grub2-unsigned	Ubuntu	lunar	*
Grub2-unsigned	Ubuntu	trusty	*
Grub2-unsigned	Ubuntu	xenial	*

Potential Mitigations

Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

https://cwe.mitre.org/data/definitions/540.html

NVD	https://nvd.nist.gov/vuln/detail/CVE-2023-4693
CWE	https://cwe.mitre.org/data/definitions/125.html

Out-of-bounds Read

Weakness

Affected Software

Potential Mitigations

References

CVE-2023-4693

Out-of-bounds Read

Weakness

Affected Software

Potential Mitigations

Related Attack Patterns

References