Container Image Risks: Why Skipping Verification Today Breaks Your Service Tomorrow

Nikita, technical leader of the Evolution Container Security and Addons team at Cloud.ru, outlines four common container security pitfalls that repeatedly appear in client Kubernetes environments. The post covers vulnerable dependencies, supply-chain attacks on image registries, secret leakage in layers, and CI/CD exposure points, supported by concrete incidents from production clusters.

Thin spot 1. Untracked vulnerabilities in dependencies

The most frequent issue is outdated software carrying known CVE entries combined with overly permissive configurations. Small teams often stay current because their infrastructure is simple, while large enterprises remain on old versions due to extensive custom integrations but compensate with strict access policies. Mid-sized organizations face the worst position: custom wrappers already hinder updates, yet they lack dedicated security staff or tooling to offset the risk.

A 2025 vulnerability in nvidia-container-toolkit (CVE-2025-23266) illustrates the danger. The flaw resided in OCI hooks that execute with host privileges. An attacker could embed a malicious library inside a minimal Dockerfile; after escaping the container, the attacker enumerated pods, located a service account with nodes/proxy rights, and used the kubelet port 10250 to execute commands on another node, ultimately accessing mounted secrets. The incident combined the NVIDIA component vulnerability with excessive service-account privileges. A second high-severity flaw appeared in the same component shortly afterward, reinforcing that privileged add-ons such as GPU operators and CNI plugins require patching within days rather than weeks.

Thin spot 2. Supply chain attacks: even pinned tags are not safe

The classic advice to avoid the latest tag proved insufficient when attackers compromised Aqua Security developer accounts in early 2026. They performed force pushes that reassigned more than seventy Trivy tags to malicious commits containing secret-exfiltration logic. Later, using a remaining compromised service account, they published tainted images directly to Docker Hub. Organizations pulling fresh images without cache or additional verification could have deployed the malicious versions.

Cloud.ru avoided impact through a private registry with caching and mandatory manual review plus secondary scanning before promotion. The incident demonstrated that a tag can be silently rebound to different content; the only reliable reference is the full SHA256 digest of the image manifest. Additional protection comes from Cosign signatures verified inside the cluster by Connaisseur, Kyverno, or Image Validating Admission Policies. The article also notes the gh0stEdit class of attacks that can alter unpacked layer contents while preserving manifest hashes.

Thin spot 3. Secret leakage: regex-based detection still works

Developers continue to commit private keys and hardcoded credentials that end up baked into container layers. Two real cases involved a DevOps engineer who left an SSH key in a working directory before pushing, and a tester who hardcoded credentials that survived the build pipeline. Simply overwriting the file or rebuilding a new image does not remove the secret from Git history or from previously pushed image layers; rotation of the secret itself remains the only reliable remediation.

Effective controls begin with pre-commit hooks that block commits containing obvious secret patterns locally. Subsequent layers include CI/CD scanning with tools such as Trivy and Checkov, followed by registry-level scanning provided by Evolution Container Security.

Thin spot 4. CI/CD as an attack vector

The article concludes by noting that supply-chain and secret issues ultimately converge in CI/CD pipelines. Automated verification of image signatures, continuous vulnerability monitoring, and strict service-account hygiene are required to prevent a single compromised upstream image or leaked credential from granting cluster-wide access.