Security restrictions bypass in QEMU



Published: 2019-07-03 | Updated: 2020-04-28
Risk Low
Patch available YES
Number of vulnerabilities 3
CVE-ID CVE-2019-13164
CVE-2019-15034
CVE-2019-15890
CWE-ID CWE-284
CWE-119
CWE-416
Exploitation vector Network
Public exploit N/A
Vulnerable software
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QEMU
Client/Desktop applications / Virtualization software

libslirp
Universal components / Libraries / Libraries used by multiple products

Vendor QEMU
Freedesktop.org

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

Updated: 28.04.2020

Added vulnerabilities #2-3, updated bulletin status to patched.

1) Improper access control

EUVDB-ID: #VU19054

Risk: Low

CVSSv3.1: 2.2 [CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-13164

CWE-ID: CWE-284 - Improper Access Control

Exploit availability: No

Description

The vulnerability allows a local attacker to gain unauthorized access to sensitive information.

The vulnerability exists due to qemu-bridge-helper.c does not ensure that a network interface name (obtained from bridge.conf or a --br=bridge option) is limited to the IFNAMSIZ size. A local attacker can create a tap device and attach it to a denied bridge interface, bypass the Access Control List (ACL) and get access to confidential data transmitted on the bridge.

Mitigation

Install update from vendor's website.

Vulnerable software versions

QEMU: 4.0.0

External links

http://www.openwall.com/lists/oss-security/2019/07/02/2
http://lists.gnu.org/archive/html/qemu-devel/2019-07/msg00145.html


Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to open a a specially crafted file.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Buffer overflow

EUVDB-ID: #VU27386

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-15034

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a local user to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error within the hw/display/bochs-display.c in QEMU due to application does not ensure a sufficient PCI config space allocation. A local user can trigger a buffer overflow and escalate privileges on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

QEMU: 4.0.0

External links

http://lists.gnu.org/archive/html/qemu-devel/2019-08/msg01959.html


Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to open a a specially crafted file.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

3) Use-after-free

EUVDB-ID: #VU20964

Risk: Medium

CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-15890

CWE-ID: CWE-416 - Use After Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists in "ip_reass()" routine in "ip_input.c" file while reassembling incoming packets, if the first fragment is bigger than the m->m_dat[] buffer. A remote attacker can send a specially crafted packet and cause the application to crash.


Mitigation

Install update from vendor's website.

Vulnerable software versions

libslirp: 4.0.0

External links

http://www.openwall.com/lists/oss-security/2019/09/06/3
http://gitlab.freedesktop.org/slirp/libslirp/commit/c5927943


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.



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