eMudhra Intermediate CA Compromise

macOS blocks the compromised intermediates, but the built-in curl, git, python3, perl, ruby, and openssl verify certificates against /etc/ssl/cert.pem without checking revocation, and that file has not been updated. To remove the affected roots from it, run:

sudo cp -p /etc/ssl/cert.pem /etc/ssl/cert.pem.bak &&
sudo awk '/^(###|===) /{skip=0}
  /^=== .*\/CN=(AAA Certificate Services|emSign ECC Root CA - G3)$/{skip=1}
  !skip' /etc/ssl/cert.pem.bak | sudo tee /etc/ssl/cert.pem > /dev/null

The built-in pip3, and the pip in virtual environments created from the built-in python3, use their own outdated copy of the roots instead. To make them use the fixed system file, run:

F="$(/usr/bin/python3 -c 'import sysconfig; print(sysconfig.get_path("stdlib"))')/sitecustomize.py" &&
echo 'import os; os.environ.setdefault("PIP_CERT", "/etc/ssl/cert.pem")' | sudo tee -a "$F" > /dev/null &&
sudo chmod 644 "$F"

For nix-darwin users, please additionally follow NixOS instructions.

Until a distribution ships an updated ca-certificates package, expert users can distrust the affected roots in the system trust store. This is NOT recommended for ordinary users.

On Debian and Ubuntu, run as root:

sed -i \
  -e 's|^mozilla/emSign_ECC_Root_CA_-_G3.crt|!&|' \
  -e 's|^mozilla/Comodo_AAA_Services_root.crt|!&|' \
  /etc/ca-certificates.conf && update-ca-certificates

If you use the Java certificate store, it might fall out of sync with your system certificate store. To sync the stores, run as root:

touch /var/lib/ca-certificates-java/fresh
dpkg-reconfigure ca-certificates-java

On Alpine, run as root:

apk add ca-certificates &&
sed -i -e 's|^mozilla/emSign_ECC_Root_CA_-_G3.crt|!&|' \
  /etc/ca-certificates.conf && update-ca-certificates

On Fedora, RHEL, CentOS Stream, Rocky Linux, AlmaLinux and Amazon Linux 2023, run as root:

d=/etc/pki/ca-trust/source/blocklist; [ -d $d ] || d=/etc/pki/ca-trust/source/blacklist
trust extract --overwrite --format=pem-bundle \
  --filter='pkcs11:object=Comodo%20AAA%20Services%20root;type=cert' \
  $d/Comodo_AAA_Services_root.pem &&
trust extract --overwrite --format=pem-bundle \
  --filter='pkcs11:object=emSign%20ECC%20Root%20CA%20-%20G3;type=cert' \
  $d/emSign_ECC_Root_CA_-_G3.pem &&
update-ca-trust

On openSUSE and SLES, run as root:

d=/etc/pki/trust/blocklist; [ -d $d ] || d=/etc/pki/trust/blacklist
trust extract --format=pem-bundle \
  --filter='pkcs11:object=Comodo%20AAA%20Services%20root;type=cert' \
  $d/Comodo_AAA_Services_root.pem &&
trust extract --format=pem-bundle \
  --filter='pkcs11:object=emSign%20ECC%20Root%20CA%20-%20G3;type=cert' \
  $d/emSign_ECC_Root_CA_-_G3.pem &&
update-ca-certificates

On Arch Linux, run as root:

trust extract --format=pem-bundle \
  --filter='pkcs11:object=emSign%20ECC%20Root%20CA%20-%20G3;type=cert' \
  /etc/ca-certificates/trust-source/blocklist/emSign_ECC_Root_CA_-_G3.pem &&
update-ca-trust

On NixOS, add to your configuration:

security.pki.caCertificateBlacklist = [
  "Comodo AAA Services root"
  "emSign ECC Root CA - G3"
];

Microsoft has shipped blocks for these certificates through Windows' automatic certificate trust list updates. Machines that receive these updates don't need this workaround. This script lets administrators block the compromised certificates locally on machines that do not, for example those that are offline or have automatic updates disabled.

This mitigation is not recommended for enterprise-managed devices. Your IT department will manage the rollout; contact them before applying local changes.

Download and inspect Block-EmudhraCompromisedCA.ps1, then run it from an elevated PowerShell terminal. Requires PowerShell 5.1 or later and the built-in Windows PKI module. This command bypasses execution policy for this process only; it does not change the machine's policy. Organization-enforced policies may still prevent execution.

powershell.exe -NoProfile -ExecutionPolicy Bypass -File .\Block-EmudhraCompromisedCA.ps1

The script imports its 16 compromised intermediates and cross-signs into LocalMachine\Disallowed (Untrusted Certificates).

This mitigation applies to clients using the Windows operating system certificate trust stores and chain validation (including Schannel TLS and Authenticode). It adds blocks to Untrusted Certificates without modifying Trusted Root Certification Authorities. Applications using independent CA bundles still need their own updates.

On NetBSD 10 and later, run as root:

certctl untrust /usr/share/certs/mozilla/all/emSign_ECC_Root_CA_-_G3.pem &&
certctl untrust /usr/share/certs/mozilla/all/Comodo_AAA_Services_root.pem

On FreeBSD 14 or later, run the following commands as root:

cp /etc/ssl/certs/14bc7599.0 /usr/share/certs/untrusted/14bc7599.pem
cp /etc/ssl/certs/ee64a828.0 /usr/share/certs/untrusted/ee64a828.pem
certctl rehash