CVE-2024-45779
Description
An integer overflow flaw was found in the BFS file system driver in grub2. When reading a file with an indirect extent map, grub2 fails to validate the number of extent entries to be read. A crafted or corrupted BFS filesystem may cause an integer overflow during the file reading, leading to a heap of bounds read. As a consequence, sensitive data may be leaked, or grub2 will crash.
Statement
To exploit this flaw, an attacker needs to trick a user into running grub2 with a specially crafted BFS file system image, limiting the exposure of this flaw. For this reason, this vulnerability has been rated with a Moderate severity.
The grub2 package as shipped in Red Hat Enterprise Linux 7, 8, 9 and in Red Hat OpenShift Container Platform 4 is not affected by this vulnerability because the BFS module is not built, so this issue is not applicable.
Mitigation
Do not run grub2 in an untrusted environment, specifically with a BFS file system image.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6 | 6 | 6 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | High | High | High |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | None | None | None |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the overflow/wraparound results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows, which can be used to execute arbitrary code. This is usually outside the scope of the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
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