CVE-2023-51780

Description

A use-after-free flaw was found in the Linux kernel's net/atm/ioctl.c (ATM networking technology driver): do_vcc_ioctl in net/atm/ioctl.c is vulnerable to use-after-free due to a race condition in vcc_recvmsg. This issue can allow an attacker to possibly gain unauthorized access, escalate privileges, or cause the system to crash.

Statement

This issue is considered to be Moderate because there is no known way to trigger kernel panic, only read incorrect buffer size because it occurs in the SIOCINQ call that returns the number of unread bytes in the receive buffer.

Mitigation

To mitigate this issue, prevent module atm from being loaded. Please see https://access.redhat.com/solutions/41278 for how to blacklist a kernel module to prevent it from loading automatically.

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).

CVSS v3 Score Breakdown

Red HatNVDcve.org
Base Score77N/A
Attack VectorLocalLocalN/A
Attack ComplexityHighHighN/A
Privileges RequiredLowLowN/A
User InteractionNoneNoneN/A
ScopeUnchangedUnchangedN/A
ConfidentialityHighHighN/A
Integrity ImpactHighHighN/A
Availability ImpactHighHighN/A

Vector

Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Red Hat CVSS v3 Score Explanation

In this case error happens for skb calculation of amount value. This one not about actual "use after free", but about return incorrect buffer size to reader. It means that local user who want to read amount of data with command like ioctl(, SIOCINQ, &) can get potentially incorrect value (as result of race condition). In most cases this should not lead to kernel panic or user software fail, because reader is responsible to read buffer anyway correctly (means should not read more than available). Overall the attack vector is Local and some privileges required (because only local user with some minimum privileges can run ioctl(, SIOCINQ, &) or similar request).

Understanding the Weakness (CWE)

Integrity

Technical Impact: Modify Memory

The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.

Availability

Technical Impact: DoS: Crash, Exit, or Restart

If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.

Confidentiality

Technical Impact: Read Memory

Read operations on freed memory can sometimes leak sensitive information instead of causing a crash

Integrity,Confidentiality,Availability

Technical Impact: Execute Unauthorized Code or Commands

If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Frequently Asked Questions

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