OpenSSH 7.9 scp input validation

CVSS Meta Temp Score
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CTI Interest Score
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5.1$0-$5k0.09

A vulnerability was found in OpenSSH 7.9 (Connectivity Software). It has been classified as critical. This affects an unknown part of the component scp. The manipulation with an unknown input leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on integrity, and availability. The summary by CVE is:

An issue was discovered in OpenSSH 7.9. Due to the scp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the scp client only performs cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious scp server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the scp client target directory. If recursive operation (-r) is performed, the server can manipulate subdirectories as well (for example, to overwrite the .ssh/authorized_keys file).

The bug was discovered 01/11/2019. The weakness was released 01/31/2019 by Harry Sintonen (Website). It is possible to read the advisory at securityfocus.com. This vulnerability is uniquely identified as CVE-2019-6111 since 01/10/2019. The exploitability is told to be difficult. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. 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 7 days. During that time the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 121296 (SUSE SLED15 / SLES15 Security Update : openssh (SUSE-SU-2019:0126-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family SuSE Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 172008 (SUSE Enterprise Linux Security Update for openssh (SUSE-SU-2019:0132-1)).

Upgrading to version 8.0 eliminates this vulnerability. The upgrade is hosted for download at openssh.com. Applying a patch is able to eliminate this problem. The bugfix is ready for download at openssh.com. The best possible mitigation is suggested to be upgrading to the latest version. A possible mitigation has been published before and not just after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (121296) and Exploit-DB (46193). Entries connected to this vulnerability are available at 129007, 130369, 130370 and 133748.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB CVSS-B Score: 🔍
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CVSSv3info

VulDB Meta Base Score: 5.3
VulDB Meta Temp Score: 5.1

VulDB Base Score: 4.8
VulDB Temp Score: 4.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.9
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
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Exploitinginfo

Class: Input validation
CWE: CWE-20
CAPEC: 🔍
ATT&CK: 🔍

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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Nessus ID: 121296
Nessus Name: SUSE SLED15 / SLES15 Security Update : openssh (SUSE-SU-2019:0126-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: OpenSSH 8.0
Patch: openssh.com

Timelineinfo

01/10/2019 🔍
01/11/2019 +1 days 🔍
01/18/2019 +7 days 🔍
01/18/2019 +0 days 🔍
01/22/2019 +4 days 🔍
01/31/2019 +9 days 🔍
01/31/2019 +0 days 🔍
02/01/2019 +1 days 🔍
07/04/2023 +1614 days 🔍

Sourcesinfo

Advisory: RHSA-2019:3702⛔
Researcher: Harry Sintonen
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2019-6111 (🔍)
SecurityFocus: 106741 - OpenSSH CVE-2019-6111 Arbitrary File Overwrite Vulnerability

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 02/01/2019 08:09
Updated: 07/04/2023 09:59
Changes: 02/01/2019 08:09 (70), 04/18/2019 11:36 (3), 05/30/2020 18:23 (9), 07/04/2023 09:59 (7)
Complete: 🔍
Committer: Simon

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