CVE-2023-27320
Description
A double-free vulnerability was found in Sudo in the per-command chroot feature. This flaw exists due to a boundary error when matching a sudoer rule that contains a per-command chroot directive (CHROOT=dir). By sending a specially-crafted request, a local privileged attacker can elevate privileges and execute arbitrary code on the system.
Statement
The CHROOT support was only added in Sudo v1.9.3 and Sudo v1.9.8 included a fix for a memory leak in the set_cmnd_path() function, which can result in the "user_cmnd" variable being freed twice, but only when processing a sudoers rule that contains a "CHROOT" setting. This does not affect the "chroot" Defaults setting. Only a per-rule "CHROOT" setting will trigger the bug.
Hence, it only affects Sudo v1.9.8 through to 1.9.13p1.
Red Hat Enterprise Linux - 6, 7, 8, 9 are shipped with lower versions of Sudo that doesn't contains the vulnerable code. Thus, they are not affected.
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 | 6.4 | 7.2 | N/A |
| Attack Vector | Local | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | High | High | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Availability
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
When a program calls free() twice with the same argument, the program's memory management data structures may become corrupted, potentially leading to the reading or modification of unexpected memory addresses. This corruption can cause the program to crash or, in some circumstances, cause two later calls to malloc() to return the same pointer. If malloc() returns the same value twice and the program later gives the attacker control over the data that is written into this doubly-allocated memory, the program becomes vulnerable to a buffer overflow attack. Doubly freeing memory may result in a write-what-where condition, allowing an attacker to execute arbitrary code.
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