Sensitive Cookie in HTTPS Session Without 'Secure' Attribute

Description

This vulnerability occurs when a web application transmits sensitive cookies over an HTTPS connection but fails to set the 'Secure' attribute on those cookies.

Extended Description

When a cookie is marked with the 'Secure' attribute, browsers guarantee it will only be sent over encrypted HTTPS connections. If this attribute is missing, even if the application initially uses HTTPS, the browser may inadvertently send the sensitive cookie over an unencrypted HTTP request. This often happens during redirects, when loading mixed content, or if a user manually types an HTTP URL, exposing session tokens or authentication data to interception. To prevent this, developers must explicitly set the 'Secure' flag for all cookies containing sensitive information in their application code. This is a critical server-side configuration that should be part of a standard secure cookie policy, alongside other attributes like 'HttpOnly' and 'SameSite'. Relying solely on HTTPS for the initial transmission is not sufficient; the 'Secure' attribute provides an essential enforcement layer at the browser level.

Common Consequences 1

Scope: Confidentiality

Impact: Read Application Data

Omitting the secure flag makes it possible for the user agent to send the cookies in plaintext over an HTTP session.

Detection Methods 1

Automated Static AnalysisHigh

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Potential Mitigations 1

Phase: Implementation

Always set the secure attribute when the cookie should be sent via HTTPS only.

Demonstrative Examples 1

The snippet of code below, taken from a servlet doPost() method, sets an accountID cookie (sensitive) without calling setSecure(true).

Code Example:Bad
Java
java

Observed Examples 4

CVE-2004-0462A product does not set the Secure attribute for sensitive cookies in HTTPS sessions, which could cause the user agent to send those cookies in plaintext over an HTTP session with the product.

CVE-2008-3663A product does not set the secure flag for the session cookie in an https session, which can cause the cookie to be sent in http requests and make it easier for remote attackers to capture this cookie.

CVE-2008-3662A product does not set the secure flag for the session cookie in an https session, which can cause the cookie to be sent in http requests and make it easier for remote attackers to capture this cookie.

CVE-2008-0128A product does not set the secure flag for a cookie in an https session, which can cause the cookie to be sent in http requests and make it easier for remote attackers to capture this cookie.