CVE-2021-22890
Published: 31 March 2021
curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly "short-cut" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.
Notes
Author | Note |
---|---|
alexmurray | affects curl versions between 7.63.0 and 7.75.0 |
Priority
Status
Package | Release | Status |
---|---|---|
curl Launchpad, Ubuntu, Debian |
bionic |
Not vulnerable
(code not present)
|
focal |
Released
(7.68.0-1ubuntu2.5)
|
|
groovy |
Released
(7.68.0-1ubuntu4.3)
|
|
trusty |
Not vulnerable
(code not present)
|
|
upstream |
Needs triage
|
|
xenial |
Not vulnerable
(code not present)
|
|
Patches: vendor: https://curl.se/EQo2A9nBnMI68.patch |
Severity score breakdown
Parameter | Value |
---|---|
Base score | 3.7 |
Attack vector | Network |
Attack complexity | High |
Privileges required | None |
User interaction | None |
Scope | Unchanged |
Confidentiality | None |
Integrity impact | Low |
Availability impact | None |
Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |