CVE-2017-7481
📋 TL;DR
CVE-2017-7481 is a critical vulnerability in Ansible where lookup plugin results were not properly marked as unsafe, allowing attackers to inject Unicode strings that could be executed as Jinja2 template code. This enables remote code execution on systems managed by Ansible. Organizations using vulnerable Ansible versions for automation are affected.
💻 Affected Systems
- Ansible
📦 What is this software?
Openstack by Redhat
Openstack by Redhat
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Full compromise of Ansible-managed systems allowing attacker to execute arbitrary commands with the privileges of the Ansible user, potentially leading to complete system takeover.
Likely Case
Attackers with access to Ansible playbooks or control over lookup inputs could execute malicious code on managed nodes, compromising infrastructure.
If Mitigated
With proper network segmentation and least privilege access, impact is limited to specific managed systems rather than entire infrastructure.
🎯 Exploit Status
Exploitation requires attacker to control lookup() inputs, which typically means they need some level of access to playbooks or the ability to influence lookup data sources.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.3.1.0 or 2.4.0.0 and later
Vendor Advisory: https://access.redhat.com/errata/RHSA-2017:1244
Restart Required: No
Instructions:
1. Update Ansible using your package manager: 'pip install --upgrade ansible>=2.3.1.0' or 'yum update ansible' 2. Verify the update completed successfully 3. Test playbooks to ensure compatibility
🔧 Temporary Workarounds
Disable Jinja2 template evaluation
allConfigure Ansible to mark Jinja2 templating as unsafe globally
Set 'jinja2_native = False' in ansible.cfg under [defaults] section
Restrict lookup plugin usage
allLimit which users can create or modify playbooks using lookup plugins
Implement strict access controls on Ansible playbook directories and version control systems
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Ansible control nodes from production systems
- Apply principle of least privilege to Ansible execution accounts and monitor for unusual activity
🔍 How to Verify
Check if Vulnerable:
Run 'ansible --version' and check if version is below 2.3.1.0 or between 2.4.0.0 and 2.4.0.0Check Version:
ansible --version | head -1Verify Fix Applied:
Confirm version is 2.3.1.0 or higher, or 2.4.0.0 or higher with 'ansible --version'📡 Detection & Monitoring
Log Indicators:
- Unusual Jinja2 template execution in Ansible logs
- Lookup plugin calls with unexpected Unicode characters
- Playbook execution errors related to template parsing
Network Indicators:
- Ansible control node connections to unexpected systems
- Unusual SSH or WinRM connections from Ansible hosts
SIEM Query:
source="ansible.log" AND ("jinja2" OR "lookup") AND ("unicode" OR "injection" OR "template error")🔗 References
- http://www.securityfocus.com/bid/98492
- https://access.redhat.com/errata/RHSA-2017:1244
- https://access.redhat.com/errata/RHSA-2017:1334
- https://access.redhat.com/errata/RHSA-2017:1476
- https://access.redhat.com/errata/RHSA-2017:1499
- https://access.redhat.com/errata/RHSA-2017:1599
- https://access.redhat.com/errata/RHSA-2017:2524
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-7481
- https://github.com/ansible/ansible/commit/ed56f51f185a1ffd7ea57130d260098686fcc7c2
- https://lists.debian.org/debian-lts-announce/2021/01/msg00023.html
- https://usn.ubuntu.com/4072-1/
- http://www.securityfocus.com/bid/98492
- https://access.redhat.com/errata/RHSA-2017:1244
- https://access.redhat.com/errata/RHSA-2017:1334
- https://access.redhat.com/errata/RHSA-2017:1476
- https://access.redhat.com/errata/RHSA-2017:1499
- https://access.redhat.com/errata/RHSA-2017:1599
- https://access.redhat.com/errata/RHSA-2017:2524
- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2017-7481
- https://github.com/ansible/ansible/commit/ed56f51f185a1ffd7ea57130d260098686fcc7c2
- https://lists.debian.org/debian-lts-announce/2021/01/msg00023.html
- https://usn.ubuntu.com/4072-1/
