CVE-2018-15869 in Web Services CLI
Summary
by MITRE
The Amazon Web Services (AWS) CLI version 1.15.85 (and possibly earlier versions) does not require the --owners flag when describing images, which makes it easier for remote attackers to trigger the loading of an undesired AMI by setting similar image properties (i.e., name), as exploited in the wild during August 2018 with a Monero miner AMI instead of the expected Ubuntu AMI.
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Analysis
by VulDB Data Team • 08/27/2025
The vulnerability identified as CVE-2018-15869 affects the Amazon Web Services Command Line Interface version 1.15.85 and potentially earlier releases, presenting a significant security risk within cloud infrastructure management operations. This flaw resides in the AWS CLI's handling of Amazon Machine Image (AMI) description commands where the system fails to enforce mandatory ownership verification through the --owners flag. The absence of this requirement creates an exploitable condition that allows adversaries to manipulate AMI selection processes through carefully crafted image properties rather than relying on proper ownership validation mechanisms. The vulnerability becomes particularly dangerous when attackers can leverage similar naming conventions to substitute malicious images for legitimate ones, as demonstrated in real-world exploitation during August 2018.
The technical implementation flaw stems from the AWS CLI's default behavior when executing describe images commands without explicit ownership parameters. Without the --owners flag, the system returns all AMIs matching the specified criteria regardless of their source or ownership status, creating a scenario where attackers can exploit the naming similarity between legitimate and malicious images. This design weakness directly violates security principles of least privilege and proper access control enforcement, as the system fails to validate the authenticity and ownership of returned images. The vulnerability maps to CWE-284 Access Control Issues, specifically addressing improper access control mechanisms that allow unauthorized access to resources through manipulated parameters. Attackers can exploit this by creating AMIs with similar names to legitimate images while ensuring the malicious AMI is either public or accessible to the target account, thereby enabling successful substitution attacks.
The operational impact of this vulnerability extends beyond simple image substitution, creating potential for sophisticated supply chain attacks within cloud environments. When attackers successfully replace legitimate Ubuntu AMIs with malicious Monero miner AMIs, they can establish persistent backdoors for cryptocurrency mining operations without requiring elevated privileges or complex exploitation techniques. This vulnerability enables attackers to maintain long-term presence in cloud environments while avoiding detection through standard access control mechanisms. The exploitation pattern demonstrates how attackers can leverage the principle of least privilege violations to gain unauthorized access to cloud resources, potentially leading to data exfiltration, resource consumption, and financial loss through unauthorized cryptocurrency mining operations. Organizations using AWS CLI without proper ownership validation can unknowingly execute malicious AMIs, creating a persistent threat vector that may remain undetected for extended periods.
Mitigation strategies for CVE-2018-15869 should focus on implementing mandatory parameter validation and enforcing proper access control mechanisms within AWS CLI operations. Organizations must ensure that all describe images commands include the --owners flag with explicit ownership specifications to prevent unauthorized image loading. The recommended approach involves implementing automated checks that enforce parameter requirements and establishing strict policies for AMI management and validation. Security teams should also implement monitoring for unusual AMI selection patterns and establish procedures for validating image ownership before execution. This vulnerability highlights the importance of following ATT&CK framework principles for cloud security operations, particularly focusing on privilege escalation and defense evasion techniques. Regular security audits of CLI usage patterns and implementation of least privilege access controls for AMI operations can significantly reduce the risk of exploitation. Additionally, organizations should consider implementing AWS Config rules and CloudTrail monitoring to detect and alert on unauthorized AMI usage patterns that could indicate exploitation attempts.