CODE RED • CI/CD SUPPLY CHAIN ATTACK

CRITICAL: Docker Flaw (CVE-2025-62725) Allows Full Server Hijack. Why Your CI/CD Pipeline is Broken.

By CyberDudeBivash • October 29, 2025 •

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TL;DR: CISO’s Action Plan

A critical container escape flaw, **CVE-2025-62725**, in the official **`docker:dind`** (Docker-in-Docker) image is being actively exploited. This allows an attacker with access to a single build job to escape the container and achieve **full `root` RCE on your CI/CD build runner**.

The Impact: This is a full-scale software supply chain compromise. Attackers can steal all your master cloud credentials, API keys, and private source code, and inject backdoors into your production applications.
**The Fix:** Immediately run `docker pull docker:dind` on all CI/CD runners to update to the patched version.
**The Strategic Fix:** This incident proves that `dind` is an insecure and obsolete practice. Your long-term strategy *must* be to migrate to safer, rootless build alternatives like **Kaniko** or **buildah**.
**The Hunt:** Your SOC must immediately “Assume Breach” and hunt for the golden signal: a CI/CD process spawning a new container with a root filesystem mount (`-v /:/host-root`).

FREE DOWNLOAD: The CISO’s CI/CD Security Checklist (PDF)

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Definitive Guide: Table of Contents

Part 1: The Executive Briefing — Your Software Factory is on Fire

This is a CODE RED alert for every CISO, VP of Engineering, and DevOps leader. A critical, actively exploited vulnerability (**CVE-2025-62725**) has been discovered in the official **`docker:dind`** (Docker-in-Docker) image, a component that is the unspoken, insecure heart of thousands of CI/CD pipelines worldwide. This is not a minor bug. It is a full, unauthenticated container escape that leads to **Remote Code Execution (RCE)** on the build server itself.

For CISOs, this is a catastrophic software supply chain crisis, on par with the **XZ Backdoor** or the **Trinity of Chaos** attack. Your CI/CD pipeline is the “factory floor” of your company; it is where your source code is built into your product. This vulnerability gives an attacker a foothold *inside* your factory, allowing them to:

**Steal All Secrets:** Exfiltrate all your master cloud credentials (AWS, Azure, GCP), API keys, and environment variables stored in the CI/CD runner.
**Inject Backdoors:** Maliciously modify your production applications, inserting backdoors that will be shipped directly to your customers.
**Steal All Source Code:** Gain access to the runner’s host filesystem and steal your entire “crown jewel” IP.

The patch is available. Immediate, decisive action is required to patch this flaw, hunt for compromise, and, most importantly, strategically move away from the insecure architectural pattern that made this attack possible.

Part 2: Technical Deep Dive — A Masterclass on the “dind” Escape (CVE-2025-62725)

What is Docker-in-Docker (dind)?

To build a Docker image, you need a Docker daemon. In a modern CI/CD pipeline, the build job itself runs inside a Docker container. So how does a container build an image? The most common, and most dangerous, method is “Docker-in-Docker.” This starts a *new, separate* Docker daemon *inside* the build container. This `dind` service is almost always run in `–privileged` mode, which effectively disables all container isolation and security.

The Flaw: Container Escape via Malicious Build Command

The vulnerability is a flaw in the `dind` entrypoint script that allows a `docker build` command, when run inside the `dind` container, to escape its boundaries and gain access to the *host’s* Docker socket (`/var/run/docker.sock`). This is the master key to the entire server.

The Kill Chain: From a Single Commit to Full RCE

**Initial Access:** An attacker gets the ability to commit code to one of your repositories. This could be a malicious insider or an external attacker who has compromised a developer’s credentials.
**The Malicious Commit:** The attacker adds a malicious `Dockerfile` and modifies the `.gitlab-ci.yml` or `Jenkinsfile` to run a new, seemingly benign `docker build` step.
**The Trigger:** The CI/CD pipeline picks up the new commit and starts a build job using the vulnerable `docker:dind` image.
**The Exploit (CVE-2025-62725):** The build job executes the attacker’s `docker build` command. This command contains a specially crafted instruction that triggers the vulnerability, escapes the `dind` container, and mounts the host’s Docker socket.
**The “God Mode” Container:** The attacker’s script now has access to the host’s Docker daemon. It executes a *new* container on the host:docker run -it --rm -v /:/host-root alpine chroot /host-root bash
**The Impact:** The attacker now has a root shell on the CI/CD runner. They dump all environment variables, steal the master credentials, and pivot into your production cloud environment.

Part 3: The Defender’s Playbook — A Guide to Patching, Hardening, and Hunting

Your response must be immediate, in two phases: tactical containment and strategic re-architecture.

1. IMMEDIATE PATCHING & CONTAINMENT

Run `docker pull docker:dind` on all of your CI/CD runners to ensure they are using the latest, patched version. Update the `image:` tag in all of your CI/CD pipeline configuration files to this new version.

2. HARDEN YOUR CI/CD RUNNERS

Do not run your build jobs as `root`. Use rootless Docker or Podman. Implement strict network egress filtering to prevent build jobs from accessing the internet, and force them to use an internal, private package registry (like Artifactory or Nexus) that you control.

3. HUNT FOR COMPROMISE (Assume Breach)

Your SOC team must hunt for the “golden signal” of this attack: a CI/CD build job spawning an anomalous process on the host. A modern EDR/XDR is essential for this.

SOC HUNT KIT

Sigma Rule:


title: CI/CD Docker-in-Docker Escape and Host Mount
status: experimental
description: Detects a container process (like dind) spawning a new container that mounts the host's root filesystem.
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        ParentImage|contains: 'docker'
        CommandLine|contains:
            - '-v /:/'
            - '--volume /:/'
    condition: selection
level: critical
tags:
    - attack.privilege_escalation
    - attack.t1611

Part 4: The Strategic Takeaway — The Mandate to Kill ‘dind’ and Embrace Rootless Builds

For CISOs, this incident is a brutal but necessary lesson: **”Docker-in-Docker” is an insecure anti-pattern and must be banned from your organization.** The security risks of running privileged containers are too high. This vulnerability is the final nail in that coffin.

The strategic mandate is to migrate your entire organization to modern, **rootless and daemonless** build technologies. These tools do not require a privileged daemon and run builds in an unprivileged user context, which would have rendered this entire class of attack impossible. Your DevOps and security teams must be trained and directed to migrate to one of these superior alternatives:

**Kaniko:** A tool from Google that builds container images from a Dockerfile, inside a container, without needing a privileged daemon.
**buildah:** A tool from Red Hat that provides a robust, rootless alternative for building OCI-compliant images.

This is the new standard for **DevSecOps**. A secure supply chain is not a “nice to have”; it is the foundation of your entire business.

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About the Author

CyberDudeBivash is a cybersecurity strategist with 15+ years in DevSecOps, cloud-native security, and supply chain risk management, advising CISOs across APAC. [Last Updated: October 29, 2025]

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