Vulnerabilities
Misconfiguration
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CVE Vulnerabilities

CVE-2020-7039

Out-of-bounds Write

Published: Jan 16, 2020 | Modified: Nov 21, 2024
CVSS 3.x
5.6
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
CVSS 2.x
6.8 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
5.6 IMPORTANT
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
Ubuntu
MEDIUM
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Additional information
NVDhttps://nvd.nist.gov/vuln/detail/CVE-2020-7039
CWEhttps://cwe.mitre.org/data/definitions/787.html

tcp_emu in tcp_subr.c in libslirp 4.1.0, as used in QEMU 4.2.0, mismanages memory, as demonstrated by IRC DCC commands in EMU_IRC. This can cause a heap-based buffer overflow or other out-of-bounds access which can lead to a DoS or potential execute arbitrary code.

Weakness

The product writes data past the end, or before the beginning, of the intended buffer.

Affected Software

NameVendorStart VersionEnd Version
LibslirpLibslirp_project4.1.0 (including)4.1.0 (including)
Advanced Virtualization for RHEL 8.1.1RedHatvirt:8.1-8010120200304224358.5db1954d*
Advanced Virtualization for RHEL 8.1.1RedHatvirt-devel:8.1-8010120200304224358.5db1954d*
Red Hat Enterprise Linux 6RedHatqemu-kvm-2:0.12.1.2-2.506.el6_10.6*
Red Hat Enterprise Linux 7RedHatqemu-kvm-10:1.5.3-173.el7*
Red Hat Enterprise Linux 7RedHatqemu-kvm-ma-10:2.12.0-44.el7*
Red Hat Enterprise Linux 7.7 Extended Update SupportRedHatqemu-kvm-10:1.5.3-167.el7_7.6*
Red Hat Enterprise Linux 7.7 Extended Update SupportRedHatqemu-kvm-ma-10:2.12.0-33.el7_7.3*
Red Hat Enterprise Linux 7 ExtrasRedHatslirp4netns-0:0.3.0-8.el7_7*
Red Hat Enterprise Linux 8RedHatcontainer-tools:rhel8-8010120200116121758.53d07e52*
Red Hat Enterprise Linux 8RedHatvirt-devel:rhel-8010020200304114113.c27ad7f8*
Red Hat Enterprise Linux 8RedHatvirt:rhel-8010020200304114113.c27ad7f8*
Red Hat Enterprise Linux 8RedHatcontainer-tools:1.0-8010020200206144344.c294d161*
Red Hat Enterprise Linux 8.0 Update Services for SAP SolutionsRedHatvirt:rhel-8000020200305185300.f8e95b4e*
Red Hat OpenShift Container Platform 4.3RedHatslirp4netns-0:0.4.2-3.git21fdece.el8*
Red Hat OpenStack Platform 10.0 (Newton)RedHatqemu-kvm-rhev-10:2.12.0-33.el7_7.10*
Red Hat OpenStack Platform 13.0 (Queens)RedHatqemu-kvm-rhev-10:2.12.0-44.el7*
Red Hat OpenStack Platform 13.0 (Queens)RedHatqemu-kvm-rhev-10:2.12.0-44.el7_8.1*
Red Hat OpenStack Platform 13.0 (Queens) for RHEL 7.6 EUSRedHatqemu-kvm-rhev-10:2.12.0-18.el7_6.11*
Red Hat Virtualization Engine 4.2RedHatqemu-kvm-rhev-10:2.12.0-18.el7_6.11*
LibslirpUbuntutrusty*
LibslirpUbuntuupstream*
QemuUbuntubionic*
QemuUbuntudisco*
QemuUbuntueoan*
QemuUbuntuesm-infra-legacy/trusty*
QemuUbuntuesm-infra/bionic*
QemuUbuntuesm-infra/xenial*
QemuUbuntutrusty*
QemuUbuntutrusty/esm*
QemuUbuntuupstream*
QemuUbuntuxenial*
Qemu-kvmUbuntuprecise/esm*
SlirpUbuntubionic*
SlirpUbuntudisco*
SlirpUbuntueoan*
SlirpUbuntuesm-apps/bionic*
SlirpUbuntuesm-apps/xenial*
SlirpUbuntuesm-infra-legacy/trusty*
SlirpUbuntutrusty*
SlirpUbuntutrusty/esm*
SlirpUbuntuupstream*
SlirpUbuntuxenial*

Potential Mitigations

  • Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

  • For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer.

  • Be wary that a language’s interface to native code may still be subject to overflows, even if the language itself is theoretically safe.

  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

  • Examples include the Safe C String Library (SafeStr) by Messier and Viega [REF-57], and the Strsafe.h library from Microsoft [REF-56]. These libraries provide safer versions of overflow-prone string-handling functions.

  • Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.

  • D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.

  • Consider adhering to the following rules when allocating and managing an application’s memory:

  • Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.

  • Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.

  • For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].

  • Use a CPU and operating system that offers Data Execution Protection (using hardware NX or XD bits) or the equivalent techniques that simulate this feature in software, such as PaX [REF-60] [REF-61]. These techniques ensure that any instruction executed is exclusively at a memory address that is part of the code segment.

  • For more information on these techniques see D3-PSEP (Process Segment Execution Prevention) from D3FEND [REF-1336].

References

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