Ethical Hacking News
A critical misconfiguration in Amazon Web Services (AWS) CodeBuild has exposed its own GitHub repositories, including its AWS JavaScript SDK, to potential supply chain attacks. This vulnerability has been dubbed "CodeBreach" and was fixed by AWS in September 2025 following responsible disclosure on August 25, 2025. The issue highlights the importance of maintaining secure continuous integration (CI) pipelines and underscores the potential risks of exploiting unauthenticated attackers' access to cloud services.
AWS CodeBuild service was vulnerable to a critical misconfiguration called "CodeBreach", which posed a significant risk to its GitHub repositories and AWS JavaScript SDK. The vulnerability allowed an attacker to inject malicious code into the build environment, potentially affecting not only applications relying on the SDK but also the Console itself. The flaw was linked to continuous integration (CI) pipelines used by CodeBuild, which could be exploited by unauthenticated attackers to breach the build environment and leak privileged credentials. The issue was found in four open-source AWS-managed GitHub repositories due to a weakness in webhook filters that failed to include essential regex pattern characters. AWS fixed the issue by remediating the misconfigured webhook filters, implementing additional mitigations, and emphasizing there was no evidence of CodeBreach being exploited in the wild. Experts recommend implementing measures to secure CI/CD pipelines, such as enabling Pull Request Comment Approval build gates, using hosted runners, and limiting PAT permissions.
Amazon Web Services (AWS), a leading provider of cloud computing services, has recently been made aware of a critical misconfiguration in its CodeBuild service. This vulnerability, codenamed "CodeBreach" by cloud security company Wiz, poses a significant risk to the organization's own GitHub repositories, including its AWS JavaScript SDK. The fix for this issue was implemented by AWS in September 2025, following responsible disclosure on August 25, 2025.
According to researchers Yuval Avrahami and Nir Ohfeld, who reported the vulnerability, CodeBreach allows an attacker to inject malicious code into the build environment, potentially affecting not only the countless applications relying on the SDK but also the Console itself. This scenario could lead to a platform-wide compromise, putting every AWS account at risk.
The flaw in question is linked to the continuous integration (CI) pipelines used by CodeBuild, which can be exploited by unauthenticated attackers to breach the build environment and leak privileged credentials such as GitHub admin tokens. Once these credentials are compromised, an attacker could push malicious code or dependencies to trusted branches within the affected repositories, thereby creating a pathway for supply chain attacks.
The issue was found in four open-source AWS-managed GitHub repositories: aws-sdk-js-v3, aws-lc, amazon-corretto-crypto-provider, and awslabs/open-data-registry. The misconfiguration involved a weakness in the webhook filters used by CodeBuild to secure against untrusted pull requests. Specifically, these filters were configured with an ACTOR_ID pattern that failed to include two essential characters – namely, the start ^ and end $ anchors. This oversight allowed any GitHub user ID that was a superstring of an approved ID (e.g., 755743) to bypass the filter and trigger builds for the affected repositories.
Researchers at Wiz were able to exploit this vulnerability by predicting new GitHub user IDs (currently 9-digits long) would "eclipse" a trusted maintainer's six-digit ID approximately every five days. This insight, combined with the use of GitHub Apps to automate app creation (which creates corresponding bot users), enabled them to generate a target ID and trigger builds that resulted in obtaining the GitHub credentials of the aws-sdk-js-v3 CodeBuild project and a Personal Access Token (PAT) belonging to the aws-sdk-js-automation user.
The compromised repositories affected by this vulnerability included those using ACTOR_ID filters, which were insufficiently anchored with necessary regex patterns. This oversight allowed attackers to bypass filter security measures and execute malicious code directly in the compromised repositories. The researchers noted that this issue serves as a "textbook example of why adversaries target CI/CD environments: a subtle, easily overlooked flaw that can be exploited for massive impact."
In response to this vulnerability, AWS remediated the identified issues by fixing the misconfigured webhook filters and implementing additional mitigations such as credential rotations and steps to secure build processes containing GitHub tokens or other credentials. The company also emphasized that it had found no evidence of CodeBreach being exploited in the wild.
To avoid a similar situation in the future, experts recommend implementing measures to secure CI/CD pipelines. This can include enabling new Pull Request Comment Approval build gates, using CodeBuild-hosted runners to manage triggers via GitHub workflows, ensuring regex patterns are anchored, generating unique PATs for each CodeBuild project, limiting PAT permissions to minimum required levels, and considering the use of dedicated unprivileged GitHub accounts for CodeBuild integration.
This vulnerability highlights the need for organizations utilizing cloud services to prioritize security in their continuous integration pipelines. By taking proactive steps to secure these environments and addressing potential weaknesses, companies can minimize the risk of supply chain attacks and protect themselves against similar vulnerabilities in the future.
Related Information:
https://www.ethicalhackingnews.com/articles/Arsenal-of-Weaknesses-The-AWS-CodeBuild-Misconfiguration-Vulnerability-Exposed-to-Potential-Supply-Chain-Attacks-ehn.shtml
https://thehackernews.com/2026/01/aws-codebuild-misconfiguration-exposed.html
https://www.infosecurity-magazine.com/news/codebuild-flaw-aws-console-risk/
https://www.wiz.io/blog/wiz-research-codebreach-vulnerability-aws-codebuild
Published: Thu Jan 15 14:44:08 2026 by llama3.2 3B Q4_K_M
