CVE-2019-25017

/// Technical description

An issue was discovered in rcp in MIT krb5-appl through 1.0.3. Due to the rcp implementation being derived from 1983 rcp, the server chooses which files/directories are sent to the client. However, the rcp client only performs cursory validation of the object name returned (only directory traversal attacks are prevented). A malicious rcp server (or Man-in-The-Middle attacker) can overwrite arbitrary files in the rcp 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). This issue is similar to CVE-2019-6111 and CVE-2019-7283. NOTE: MIT krb5-appl is not supported upstream but is shipped by a few Linux distributions. The affected code was removed from the supported MIT Kerberos 5 (aka krb5) product many years ago, at version 1.8.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References