CVE-2023-1170
Description
A heap-based buffer overflow vulnerability was found in Vim's utf_ptr2char() function of the src/mbyte.c file. This flaw occurs because there is access to invalid memory with put in visual block mode. An attacker can trick a user into opening a specially crafted file, triggering an out-of-bounds read that causes an application to crash, leading to a denial of service.
Statement
Red Hat Product Security has rated this issue as having a Low security impact, because the "victim" has to run an untrusted file IN SCRIPT MODE. Someone who is running untrusted files in script mode is equivalent to someone just taking a random python script and running it.
Since Red Hat Enterprise Linux 6, 7 are Out-of-Support-Scope for Low/Moderate flaws, the issue is not currently planned to be addressed in future updates for RHEL-6,7. Only Important and Critical severity flaws will be addressed at this time.
For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/ and Red Hat Enterprise Linux Life Cycle & Updates Policy: https://access.redhat.com/support/policy/updates/errata/.
Mitigation
Untrusted vim scripts with -s [scriptin] are not recommended to run.
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 | 5.3 | 6.6 | 7.3 |
| Attack Vector | Local | Local | Local |
| Attack Complexity | Low | Low | Low |
| Privileges Required | None | None | Low |
| User Interaction | Required | Required | Required |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | Low | Low | High |
| Integrity Impact | Low | Low | High |
| Availability Impact | Low | High | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
NVD: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H
cve.org: CVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
C:L, I:L:- because as per attack scenario, the victim user running vim with a malicious file (e.g. coming from an attacker) in -s [Script mode]. As such a crash or an out-of-bound read does not pose any real security risk, unless it can be proven that the triggered oob-read can be used to send/modify valuable information to/by a remote/local attacker. So, most likely it will cause DoS, and crashing the application would not be a persistent denial of service, as application should be relaunched and victim needs to reopen the malicious file again to re-crash. Hence, A:L.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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