How to deal with certificates using Selenium?

Question

For the Firefox, you need to set accept_untrusted_certs FirefoxProfile() option to True:

from selenium import webdriver

profile = webdriver.FirefoxProfile()
profile.accept_untrusted_certs = True

driver = webdriver.Firefox(firefox_profile=profile)
driver.get('https://cacert.org/')

driver.close()

For Chrome, you need to add --ignore-certificate-errors ChromeOptions() argument:

from selenium import webdriver

options = webdriver.ChromeOptions()
options.add_argument('ignore-certificate-errors')

driver = webdriver.Chrome(chrome_options=options)
driver.get('https://cacert.org/')

driver.close()

For the Internet Explorer, you need to set acceptSslCerts desired capability:

from selenium import webdriver

capabilities = webdriver.DesiredCapabilities().INTERNETEXPLORER
capabilities['acceptSslCerts'] = True

driver = webdriver.Ie(capabilities=capabilities)
driver.get('https://cacert.org/')

driver.close()

---

Actually, according to the Desired Capabilities documentation, setting acceptSslCerts capability to True should work for all browsers since it is a generic read/write capability:

acceptSslCerts

boolean

Whether the session should accept all SSL certs by default.

---

Working demo for Firefox:

>>> from selenium import webdriver

Setting acceptSslCerts to False:

>>> capabilities = webdriver.DesiredCapabilities().FIREFOX
>>> capabilities['acceptSslCerts'] = False
>>> driver = webdriver.Firefox(capabilities=capabilities)
>>> driver.get('https://cacert.org/')
>>> print(driver.title)
Untrusted Connection
>>> driver.close()

Setting acceptSslCerts to True:

>>> capabilities = webdriver.DesiredCapabilities().FIREFOX
>>> capabilities['acceptSslCerts'] = True
>>> driver = webdriver.Firefox(capabilities=capabilities)
>>> driver.get('https://cacert.org/')
>>> print(driver.title)
Welcome to CAcert.org
>>> driver.close()

For Firefox:

ProfilesIni profile = new ProfilesIni();
FirefoxProfile myprofile = profile.getProfile("default");
myprofile.setAcceptUntrustedCertificates(true);
myprofile.setAssumeUntrustedCertificateIssuer(true);
WebDriver driver = new FirefoxDriver(myprofile);

For Chrome we can use:

DesiredCapabilities capabilities = DesiredCapabilities.chrome();
capabilities.setCapability("chrome.switches", Arrays.asList("--ignore-certificate-errors"));
driver = new ChromeDriver(capabilities);

For Internet Explorer we can use:

DesiredCapabilities capabilities = new DesiredCapabilities();
capabilities.setCapability(CapabilityType.ACCEPT_SSL_CERTS, true);      
Webdriver driver = new InternetExplorerDriver(capabilities);

For Firefox Python:

The Firefox Self-signed certificate bug has now been fixed: accept ssl cert with marionette firefox webdrive python splinter

"acceptSslCerts" should be replaced by "acceptInsecureCerts"

from selenium import webdriver
from selenium.webdriver.common.desired_capabilities import DesiredCapabilities
from selenium.webdriver.firefox.firefox_binary import FirefoxBinary

caps = DesiredCapabilities.FIREFOX.copy()
caps['acceptInsecureCerts'] = True
ff_binary = FirefoxBinary("path to the Nightly binary")

driver = webdriver.Firefox(firefox_binary=ff_binary, capabilities=caps)
driver.get("https://expired.badssl.com")

For people coming to this question related to headless chrome via python selenium, you may find https://bugs.chromium.org/p/chromium/issues/detail?id=721739#c102 to be useful.

It looks like you can either do

chrome_options = Options()
chrome_options.add_argument('--allow-insecure-localhost')

or something along the lines of the following (may need to adapt for python):

ChromeOptions options = new ChromeOptions()
DesiredCapabilities caps = DesiredCapabilities.chrome()
caps.setCapability(ChromeOptions.CAPABILITY, options)
caps.setCapability("acceptInsecureCerts", true)
WebDriver driver = new ChromeDriver(caps)

And in C# (.net core) using Selenium.Webdriver and Selenium.Chrome.Webdriver like this:

ChromeOptions options = new ChromeOptions();
options.AddArgument("--ignore-certificate-errors");
using (var driver = new ChromeDriver(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location),options))
{ 
  ...
}

    ChromeOptions options = new ChromeOptions().addArguments("--proxy-server=http://" + proxy);
    options.setAcceptInsecureCerts(true);