#VU9609 Security restrictions bypass in Rsync - CVE-2017-17434

Vulnerability identifier: #VU9609

Vulnerability risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-17434

CWE-ID: CWE-284

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Rsync
Server applications / Other server solutions

Vendor: Samba

Description
The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The weakness exists due to the daemon  does not check for fnamecmp filenames in the daemon_filter_list data structure (in the recv_files function in receiver.c) and also does not apply the sanitize_paths protection mechanism to pathnames found in "xname follows" strings (in the read_ndx_and_attrs function in rsync.c) and bypass intended access restrictions.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Rsync: 3.1.2 - 3.1.3

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External links
https://git.samba.org/?p=rsync.git;a=commit;h=3e06d40029cfdce9d0f73d87cfd4edaf54be9c51

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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 Internet.

Is there known malware, which exploits this vulnerability?

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