Several security vulnerabilities were discovered in inetutils, a collection of common network programs.
inetutils' ftp client before 2.2 does not validate addresses
returned by PSV/LSPV responses to make sure they match the server
address. A malicious server can exploit this flaw to reach services
in the client's private network. (This is similar to curl's
inetutils's telnet server through 2.3 has a NULL pointer dereference
which a client can trigger by sending 0xff 0xf7 or 0xff 0xf8. In a
typical installation, the telnetd application would crash but the
telnet service would remain available through inetd. However, if the
telnetd application has many crashes within a short time interval,
the telnet service would become unavailable after inetd logs a
"telnet/tcp server failing (looping), service terminated" error.
For Debian 9 stretch, these problems have been fixed in version 2:1.9.4-2+deb9u2.
We recommend that you upgrade your inetutils packages.
Further information about Extended LTS security advisories can be found in the dedicated section of our website.