Vulnerability identifier: #VU50871

Vulnerability risk: Medium

CVSSv3: 6.5 [CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20247

CWE-ID: CWE-22

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Isync: mailbox synchronizer
Other software / Other software solutions

Vendor: ossi

Description

The vulnerability allows a remote attacker to perform directory traversal attacks.

The vulnerability exists due to improper validation of mailbox names returned by IMAP LIST/LSUB in the mbsync command. A remote attacker can send a specially crafted HTTP request and read arbitrary files on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Isync: mailbox synchronizer: 1.3.4, 1.4.0

CPE

• cpe:/a:ossi:isync:_mailbox_synchronizer:1.4.0:
• cpe:/a:ossi:isync:_mailbox_synchronizer:1.3.4:

External links
https://seclists.org/oss-sec/2021/q1/170

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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.