#VU16541 Path traversal in QEMU - CVE-2018-16872

Vulnerability identifier: #VU16541

Vulnerability risk: Low

CVSSv4.0: 4.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2018-16872

CWE-ID: CWE-22

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
QEMU
Client/Desktop applications / Virtualization software

Vendor: QEMU

Description

The vulnerability allows an adjacent attacker to obtain potentially sensitive information on the target system.

The vulnerability exists in qemu Media Transfer Protocol (MTP) due to the code opening files in usb_mtp_get_object and usb_mtp_get_partial_object and directories in usb_mtp_object_readdir doesn't consider that the underlying filesystem may have changed since the time lstat(2) was called in usb_mtp_object_alloc, a classical TOCTTOU problem. An adjacent attacker with write access to the host filesystem shared with a guest can use this property to navigate the host filesystem in the context of the QEMU process and read any file the QEMU process has access to.

Mitigation
Update to version 3.1.0.

Vulnerable software versions

QEMU: 2.0 - 3.0.0

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External links
https://lists.gnu.org/archive/html/qemu-devel/2018-12/msg03135.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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