PSFTPd 10.0.4 Build 729 sftp use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.4$0-$5k0.00

A vulnerability was found in PSFTPd 10.0.4 Build 729 (File Transfer Software). It has been classified as problematic. Affected is an unknown code of the component sftp. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on availability. CVE summarizes:

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.

The bug was discovered 11/10/2017. The weakness was presented 11/15/2017 as not defined posting (Bugtraq). The advisory is shared for download at securityfocus.com. This vulnerability is traded as CVE-2017-15271 since 10/11/2017. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. Technical details are unknown but a public exploit is available.

The exploit is shared for download at exploit-db.com. It is declared as proof-of-concept. The vulnerability was handled as a non-public zero-day exploit for at least 5 days. During that time the estimated underground price was around $0-$5k.

It is possible to mitigate the weakness by firewalling .

The vulnerability is also documented in the vulnerability database at Exploit-DB (43144). See 109426, 109427 and 109429 for similar entries.

Productinfo

Type

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv3info

VulDB Meta Base Score: 5.6
VulDB Meta Temp Score: 5.4

VulDB Base Score: 5.3
VulDB Temp Score: 4.9
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.9
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Firewall
Status: 🔍

0-Day Time: 🔍

Timelineinfo

10/11/2017 🔍
11/10/2017 +30 days 🔍
11/15/2017 +5 days 🔍
11/15/2017 +0 days 🔍
11/16/2017 +1 days 🔍
01/10/2023 +1881 days 🔍

Sourcesinfo

Advisory: 144972⛔
Status: Not defined

CVE: CVE-2017-15271 (🔍)
scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 11/16/2017 10:32 AM
Updated: 01/10/2023 01:26 PM
Changes: 11/16/2017 10:32 AM (60), 12/06/2019 04:53 PM (4), 01/10/2023 01:26 PM (4)
Complete: 🔍

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