IAM policies are like layered security badges\u2014one might deny you entry, but you’re in if another gives you an all-access pass. This is AWS IAM Policy Shadowing.<\/p>\n\n\n\n
If you’re managing AWS IAM policies, you probably feel pretty confident about your security controls. But what if I told you there\u2019s a hidden risk that could be giving users more access than you intended\u2014without you even realizing it? This journey is as much about me learning as it is about sharing what I find. Let’s explore IAM Policy Shadowing<\/strong> together.<\/p>\n\n\n\n AWS IAM is powerful but complex. With policies layered across users, roles, groups, permission boundaries, service control policies (SCPs), and resource-based policies, it\u2019s easy for one policy to override another in unexpected ways. I\u2019ve started digging into this: when an explicitly denied action still gets allowed or permissions don\u2019t behave the way you expect.<\/p>\n\n\n\n Let\u2019s uncover how IAM Policy Shadowing<\/strong> happens, why it\u2019s a security risk, and what we can do about it.<\/p>\n\n\n\n IAM Policy Shadowing occurs when one policy unintentionally overrides another, creating excessive permissions or ineffective restrictions. This usually happens when multiple policies interact in ways that aren’t immediately obvious. Here are some examples:<\/p>\n\n\n\n At first glance, your IAM policies might look solid, but shadowing can creep in silently. That\u2019s why I\u2019m making this my focus\u2014if it’s tripping me up, I’m sure others are facing it too.<\/p>\n\n\n\n Policy shadowing can lead to users or services having permissions beyond what was intended. This could allow a developer to delete critical resources, an attacker to escalate privileges, or a misconfigured automation script to make unintended changes.<\/p>\n\n\n\n Security frameworks like ISO 27001, SOC2, and NIST<\/strong> require strict access control. Shadowed policies can make it seem like permissions are restricted when, in reality, a different policy might be granting unexpected access.<\/p>\n\n\n\n AWS IAM policies follow a specific policy evaluation logic<\/strong> (which I\u2019ll dive into in future posts). Shadowing issues aren\u2019t always apparent unless you analyze how multiple policies interact.<\/p>\n\n\n\n Let\u2019s say you apply an SCP at the organizational unit (OU) level to prevent users from deleting S3 buckets:<\/p>\n\n\n\n However, an inline IAM policy attached to a developer role includes:<\/p>\n\n\n\n If the SCP should override all IAM policies, then the delete action should be blocked, right? Not necessarily! Another attached policy could override the deny<\/strong>, allowing deletion depending on where the policies are applied. Understanding the interaction between IAM policies, SCPs, permission boundaries, and resource-based policies is crucial.<\/p>\n\n\n\n This is just the beginning. Over the next few months, I\u2019ll be:<\/p>\n\n\n\n \u2705 Exploring how to detect AWS IAM Policy Shadowing using native tools<\/strong> (IAM Access Analyzer, CloudTrail, AWS Config, and third-party tools). If you\u2019ve encountered IAM policies behaving in unexpected ways, let\u2019s talk! Share your experiences, questions, or horror stories\u2014I\u2019d love to hear them. I\u2019ll be posting regularly, and I\u2019ll incorporate your feedback and challenges into upcoming posts.<\/p>\n\n\n\n Stay tuned for next month\u2019s deep dive: How to Detect IAM Policy Shadowing in AWS Using Built-in Tools.<\/strong><\/p>\n\n\n\n Let\u2019s demystify IAM policies together.<\/p>\n\n\n\n IAM policies are like layered security badges\u2014one might deny you entry, but you’re in if another gives you an all-access pass. This is AWS IAM Policy Shadowing. If you’re managing AWS IAM policies, you probably feel pretty confident about your security controls. But what if I told you there\u2019s a hidden risk that could be…<\/p>\n","protected":false},"author":2,"featured_media":1178,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[12,17],"tags":[53,41,55,46,64,68,43,52,58,70,62,57,49,48,50,45,59,60,54,67,42,69,51,56,66,47,65,61,63,44],"class_list":["post-1173","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-techniques","category-tools","tag-aws-compliance","tag-aws-iam","tag-aws-iam-access-analyzer","tag-aws-iam-best-practices","tag-aws-iam-best-practices-2024","tag-aws-iam-compliance-risks","tag-aws-iam-policy","tag-aws-iam-policy-conflicts","tag-aws-iam-policy-evaluation","tag-aws-iam-policy-tools","tag-aws-iam-policy-troubleshooting","tag-aws-iam-role-configuration","tag-aws-iam-troubleshooting","tag-aws-identity-and-access-management","tag-aws-least-privilege","tag-aws-permissions","tag-aws-policy-simulator","tag-aws-privilege-escalation","tag-aws-role-based-access-control","tag-aws-scps-vs-iam-policies","tag-aws-security","tag-aws-security-audit","tag-aws-security-best-practices","tag-aws-security-hub","tag-aws-security-misconfigurations","tag-cloud-security","tag-detecting-excessive-aws-permissions","tag-fixing-aws-iam-policies","tag-how-to-secure-aws-iam","tag-iam-policy-shadowing"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/badbadger.tech\/index.php?rest_route=\/wp\/v2\/posts\/1173","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/badbadger.tech\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/badbadger.tech\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/badbadger.tech\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/badbadger.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1173"}],"version-history":[{"count":2,"href":"https:\/\/badbadger.tech\/index.php?rest_route=\/wp\/v2\/posts\/1173\/revisions"}],"predecessor-version":[{"id":1176,"href":"https:\/\/badbadger.tech\/index.php?rest_route=\/wp\/v2\/posts\/1173\/revisions\/1176"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/badbadger.tech\/index.php?rest_route=\/wp\/v2\/media\/1178"}],"wp:attachment":[{"href":"https:\/\/badbadger.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1173"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/badbadger.tech\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1173"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/badbadger.tech\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1173"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n\n\n\nWhat is AWS IAM Policy Shadowing?<\/strong><\/h2>\n\n\n\n
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Why is This a Problem?<\/strong><\/h3>\n\n\n\n
1. Unintended Privilege Escalation<\/strong><\/h4>\n\n\n\n
2. Compliance and Audit Failures<\/strong><\/h4>\n\n\n\n
3. Difficult to Detect and Troubleshoot<\/strong><\/h4>\n\n\n\n
\n\n\n\nExample Scenario: When Policies Clash<\/strong><\/h3>\n\n\n\n
{
\"Effect\": \"Deny\",
\"Action\": \"s3:DeleteBucket\",
\"Resource\": \"*\"
}<\/pre>\n\n\n\n{\n \"Effect\": \"Allow\",\n \"Action\": \"s3:*\",\n \"Resource\": \"*\"\n}<\/code><\/pre>\n\n\n\nWhat\u2019s Next?<\/strong><\/h3>\n\n\n\n
\u2705 Breaking down AWS IAM Policy Shadowing evaluation logic<\/strong> to understand why shadowing happens.
\u2705 Showing hands-on examples of fixing policy conflicts<\/strong> with real-world scenarios.
\u2705 Discussing compliance risks and how to document IAM controls properly.<\/strong><\/p>\n\n\n\nJoin Me on This Learning Journey<\/strong><\/h3>\n\n\n\n
Where to Learn More<\/strong><\/h3>\n\n\n\n
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