We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Why does Firefox get "SecureConnectionFailed - PR_CONNECT_ABORTED_ERROR" when connecting to website that has the SHA1 hash disabled?

SPI_help
SPI_help
more options

Security consultants have advised that cipher suites using the SHA1 hash are no longer considered secure and should not be enabled.

Using the nmap tool we can identify which cipher suites use the SHA1 hash.

On our webserver, (IIS version 8.5 on Windows 2012 R2 ) if we eliminate cipher suites that contain the SHA1 hash, the Firefox browser cannot browse the site. Error displayed = Secure Connection Failed - PR_CONNECT_ABORTED_ERROR We tested versions up to Firefox ( v75.0 ).

Other browsers such as Chrome and IE have no issues browsing our site with the SHA1 hash disabled.

Once the SHA1 hash is enabled, Firefox works fine. Seeking a solution that will satisfy the security folks and our Firefox users.

Security consultants have advised that cipher suites using the SHA1 hash are no longer considered secure and should not be enabled. Using the nmap tool we can identify which cipher suites use the SHA1 hash. On our webserver, (IIS version 8.5 on Windows 2012 R2 ) if we eliminate cipher suites that contain the SHA1 hash, the Firefox browser cannot browse the site. Error displayed = Secure Connection Failed - PR_CONNECT_ABORTED_ERROR We tested versions up to Firefox ( v75.0 ). Other browsers such as Chrome and IE have no issues browsing our site with the SHA1 hash disabled. Once the SHA1 hash is enabled, Firefox works fine. Seeking a solution that will satisfy the security folks and our Firefox users.
Attached screenshots

All Replies (1)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 10 Contributor
more options

You can see the ones supported by Firefox by visiting this page in Firefox:

https://clienttest.ssllabs.com:8443/ssltest/viewMyClient.html

The ones in green text do not use SHA1. You'll notice 3 ciphers for TLS 1.3, then 3 ciphers for RSA (TLS_ECDHE_RSA) and 3 ciphers for ECDSA (TLS_ECDHE_ECDSA) certificates.

According to https://docs.microsoft.com/en-us/wind.../tls-cipher-suites-in-windows-8-1, you might not be able to connect using an RSA certificate: Windows Server 2012 R2 appears only to have "CBC" ciphers for SHA256 and SHA384, and Firefox only has "CBC" ciphers below that level. However, with an ECDSA certificate, there appears to be an overlap:

  • TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
  • TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256