CVE-2017-12872 in SimpleSAMLphp
Summary
by MITRE
The (1) Htpasswd authentication source in the authcrypt module and (2) SimpleSAML_Session class in SimpleSAMLphp 1.14.11 and earlier allow remote attackers to conduct timing side-channel attacks by leveraging use of the standard comparison operator to compare secret material against user input.
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Analysis
by VulDB Data Team • 12/27/2022
The vulnerability identified as CVE-2017-12872 affects SimpleSAMLphp versions 1.14.11 and earlier, specifically targeting the authentication mechanisms within the authcrypt module and SimpleSAML_Session class. This flaw represents a critical timing side-channel attack vulnerability that exploits the use of standard string comparison operators when validating secret material against user input. The vulnerability stems from the predictable execution time patterns that occur during authentication processes, where attackers can measure the time taken for comparison operations to infer information about secret values.
The technical implementation of this vulnerability occurs when the system employs standard comparison operators such as == or === to evaluate user-provided credentials against stored secret values. In traditional programming languages, these operators perform character-by-character comparison from left to right, meaning that if the first few characters match, the system continues checking subsequent characters. This behavior creates measurable timing differences that an attacker can exploit through carefully crafted timing measurements to gradually deduce the correct secret value. The vulnerability specifically impacts the Htpasswd authentication source within the authcrypt module and the SimpleSAML_Session class, both of which handle sensitive authentication data.
From an operational perspective, this vulnerability enables remote attackers to conduct sophisticated timing attacks that can compromise authentication systems without requiring direct access to the underlying infrastructure. The attack vector is particularly dangerous because it can be executed over network connections, making it accessible to attackers anywhere in the world. The impact extends beyond simple credential theft, as successful exploitation could lead to unauthorized access to protected systems, data breaches, and potential lateral movement within compromised networks. The vulnerability aligns with CWE-347, which addresses improper verification of cryptographic signatures, and represents a classic example of a timing side-channel attack that violates fundamental security principles.
The mitigation strategies for this vulnerability involve implementing constant-time comparison algorithms that ensure the comparison operation takes the same amount of time regardless of the input values. Organizations should upgrade to SimpleSAMLphp versions 1.14.12 and later, where the issue has been resolved through the implementation of secure string comparison functions. Additionally, security teams should conduct comprehensive vulnerability assessments to identify any custom implementations that might be susceptible to similar timing attacks. The remediation process should also include monitoring for anomalous authentication patterns that might indicate timing attack attempts. This vulnerability demonstrates the importance of adhering to security best practices such as those outlined in the OWASP Top Ten and aligns with ATT&CK technique T1212, which covers exploitation for credential access through timing attacks. Organizations must ensure that all authentication systems implement constant-time comparison operations to prevent similar vulnerabilities from being exploited in the future.