FreeBSD VuXML: Documenting security issues in FreeBSD and the FreeBSD Ports Collection

Python -- smtplib StartTLS stripping vulnerability

Affected packages
python27 < 2.7.12
0 < python33
python34 < 3.4.5
python35 < 3.5.2


VuXML ID 8d5368ef-40fe-11e6-b2ec-b499baebfeaf
Discovery 2016-06-14
Entry 2016-07-03

Red Hat reports:

A vulnerability in smtplib allowing MITM attacker to perform a startTLS stripping attack. smtplib does not seem to raise an exception when the remote end (smtp server) is capable of negotiating starttls but fails to respond with 220 (ok) to an explicit call of SMTP.starttls(). This may allow a malicious MITM to perform a startTLS stripping attack if the client code does not explicitly check the response code for startTLS.


CVE Name CVE-2016-0772