CVE-2017-15271

moderate-risk
Published 2017-11-15

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.

Do I need to act?

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19.3% chance of exploitation in next 30 days
EPSS score — higher than 81% of all CVEs
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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1 public exploit available
43144
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
5
CVSS 5.9/10 Medium
NETWORK / HIGH complexity

Affected Products (1)

Affected Vendors

Psftp

References (8)

Third Party Advisory http://packetstormsecurity.com/files/144972/PSFTPd-Windows-FTP-Server-10.0.4-Bui...
http://www.securityfocus.com/archive/1/541518/100/0/threaded
Third Party Advisory https://www.exploit-db.com/exploits/43144/
Third Party Advisory https://www.x41-dsec.de/lab/advisories/x41-2017-006-psftpd/
Third Party Advisory http://packetstormsecurity.com/files/144972/PSFTPd-Windows-FTP-Server-10.0.4-Bui...
http://www.securityfocus.com/archive/1/541518/100/0/threaded
Third Party Advisory https://www.exploit-db.com/exploits/43144/
Third Party Advisory https://www.x41-dsec.de/lab/advisories/x41-2017-006-psftpd/
37
/ 100
moderate-risk
Severity 18/34 · Moderate
Exploitability 14/34 · Moderate
Exposure 5/34 · Minimal