CVE-2017-15271 Information

Description

A use-after-free issue could be triggered remotely in the SFTP component of PSFTPd 10.0.4 Build 729. This issue could be triggered prior to authentication. The PSFTPd server did not automatically restart which enabled attackers to perform a very effective DoS attack against this service. By sending a crafted SSH identification / version string to the server a NULL pointer dereference could be caused apparently because of a race condition in the window message handling performing the cleanup for invalid connections. This incorrect cleanup code has a use-after-free.

CVSS Vector

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Reference

http://packetstormsecurity.com/files/144972/PSFTPd-Windows-FTP-Server-10.0.4-Build-729-Use-After-Free-Log-Injection.html http://www.securityfocus.com/archive/1/541518/100/0/threaded https://www.exploit-db.com/exploits/43144/ https://www.x41-dsec.de/lab/advisories/x41-2017-006-psftpd/

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

NONE

Base Score

HIGH

Base Severity

5.9