Directory Traversal Affecting openssh-server package, versions <0:7.4p1-16.amzn2.0.6


Severity

Recommended
0.0
medium
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
58.2% (99th percentile)

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  • Snyk IDSNYK-AMZN2-OPENSSHSERVER-1670486
  • published27 Sept 2021
  • disclosed31 Jan 2019

Introduced: 31 Jan 2019

CVE-2019-6111  (opens in a new tab)
CWE-22  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2 openssh-server to version 0:7.4p1-16.amzn2.0.6 or higher.
This issue was patched in ALAS2-2019-1216.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssh-server package and not the openssh-server package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2 relevant fixed versions and status.

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).

References

CVSS Base Scores

version 3.1