CVE-2020-8608
Description
An out-of-bounds heap buffer access flaw was found in the SLiRP networking implementation of the QEMU emulator. This flaw occurs in tcp_emu() routine while emulating IRC and other protocols due to unsafe usage of the snprintf(3) function. A user or process could use this flaw to crash the QEMU process on the host, resulting in a denial of service or potential execution of arbitrary code with privileges of the QEMU process on the host.
Statement
This issue affects user-mode or SLiRP networking implementation of the QEMU emulator. Though qemu-kvm package is built with SLiRP networking support, due to its limitations, it is not used by the virtual machine guests by default.
This issue affects versions of the qemu-kvm package as shipped with Red Hat Enterprise Linux 5, 6, 7, 8 and Red Hat Enterprise Linux Advanced Virtualization 8. Future qemu-kvm package updates for Red Hat Enterprise Linux 6, 7, 8 and Red Hat Enterprise Linux Advanced Virtualization 8 may address this issue.
Red Hat Enterprise Linux 5 is now in Maintenance Support 2 Phase of the support and maintenance life cycle. This issue is currently not planned to be addressed in its future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
Red Hat OpenStack Platform:
This flaw impacts KVM user-mode or SLIRP networking, which is not used in Red Hat OpenStack Platform. Although updating is recommended for affected versions (see below), Red Hat OpenStack Platform environments are not vulnerable.
Mitigation
This issue can only be resolved by applying updates.
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
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 Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.6 | 5.6 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | Low | Low | N/A |
| Availability Impact | Low | Low | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)
Buffer overflows generally lead to crashes. Other attacks leading to lack of availability are possible, including putting the program into an infinite loop.
Integrity,Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Modify Memory
Buffer overflows often can be used to execute arbitrary code, which is usually outside the scope of a program's implicit security policy. Besides important user data, heap-based overflows can be used to overwrite function pointers that may be living in memory, pointing it to the attacker's code. Even in applications that do not explicitly use function pointers, the run-time will usually leave many in memory. For example, object methods in C++ are generally implemented using function pointers. Even in C programs, there is often a global offset table used by the underlying runtime.
Integrity,Confidentiality,Availability,Access Control,Other
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Other
When the consequence is arbitrary code execution, this can often be used to subvert any other security service.
Acknowledgements
Red Hat would like to thank Laszlo Ersek (redhat.com) for reporting this issue.
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