如果會話超時時間過長，攻擊者就會有更多時間危害用戶帳戶。
會話持續時間越長，攻擊者危害用戶帳戶的機會就越大。當會話處于活動狀態時，攻擊者可能會強力攻擊用戶的密碼、破解用戶的無線密鑰或者通過打開的瀏覽器強占會話。如果創建大量的會話，較長的會話超時時間還會阻止系統釋放內存，并最終導致 denial of service。
例 1：如果會話超時時間為零或小于零，會話永遠都不會過期。以下示例顯示，如果會話超時時間設置為 -1，則會導致此會話永遠保持活動狀態。
<session-config>
<session-timeout>-1</session-timeout>
</session-config>
<session-timeout> 標記為 Web 應用程序中的所有會話定義默認的會話超時間隔。如果缺少 <session-timeout> 標記，則由容器來設置默認超時間隔。
[1] Standards Mapping - OWASP Top 10 2004 - (OWASP 2004) A3 Broken Authentication and Session Management
[2] Standards Mapping - OWASP Top 10 2010 - (OWASP 2010) A3 Broken Authentication and Session Management
[3] Standards Mapping - OWASP Top 10 2007 - (OWASP 2007) A7 Broken Authentication and Session Management
[4] Standards Mapping - Security Technical Implementation Guide Version 3 - (STIG 3) APP3415 CAT II
[5] Standards Mapping - Security Technical Implementation Guide Version 3.4 - (STIG 3.4) APP3415 CAT II
[6] Standards Mapping - Common Weakness Enumeration - (CWE) CWE ID 613
[7] Standards Mapping - FIPS200 - (FISMA) IA
[8] Standards Mapping - Web Application Security Consortium 24 + 2 - (WASC 24 + 2) Insufficient Session Expiration
[9] Sun Microsystems, Inc. Java Servlet Specification 2.4
[10] Standards Mapping - Payment Card Industry Data Security Standard Version 1.1 - (PCI 1.1) Requirement 6.5.3, Requirement 8.5.15
[11] Standards Mapping - Payment Card Industry Data Security Standard Version 1.2 - (PCI 1.2) Requirement 6.5.7, Requirement 8.5.15
[12] Standards Mapping - Payment Card Industry Data Security Standard Version 2.0 - (PCI 2.0) Requirement 6.5.8, Requirement 8.5.15