CVE-2021-40503 in GUI
Summary
by MITRE • 11/10/2021
An information disclosure vulnerability exists in SAP GUI for Windows - versions < 7.60 PL13, 7.70 PL4, which allows an attacker with sufficient privileges on the local client-side PC to obtain an equivalent of the user’s password. With this highly sensitive data leaked, the attacker would be able to logon to the backend system the SAP GUI for Windows was connected to and launch further attacks depending on the authorizations of the user.
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Analysis
by VulDB Data Team • 11/12/2021
The vulnerability identified as CVE-2021-40503 represents a critical information disclosure flaw within SAP GUI for Windows client software, affecting multiple version ranges including releases prior to 7.60 PL13 and 7.70 PL4. This vulnerability exposes a fundamental security weakness in how the application handles authentication credentials, creating a pathway for attackers to extract sensitive user authentication data from the local client environment. The flaw specifically targets the client-side component of SAP GUI for Windows, which serves as the primary interface for users to interact with SAP backend systems, making it a prime target for attackers seeking to escalate their privileges and gain unauthorized access to enterprise SAP environments.
The technical implementation of this vulnerability stems from improper handling of user credentials within the SAP GUI client, where authentication tokens or password equivalents are stored or transmitted in a manner that exposes them to local attackers with sufficient privileges. This type of flaw aligns with CWE-200, which addresses information exposure, and represents a classic example of credential leakage through insecure local storage mechanisms. The vulnerability operates at the client-side execution context where an attacker with local access can potentially extract sensitive information that would normally remain protected within the application's secure boundaries. The attacker's ability to obtain what is essentially an equivalent of the user's password indicates that the system is not properly implementing secure credential storage practices, potentially storing authentication data in plaintext or using weak encryption methods.
From an operational impact perspective, this vulnerability creates a severe risk for organizations relying on SAP GUI for Windows as their primary client interface. The exploitation of this flaw enables attackers to perform lateral movement attacks against SAP backend systems, potentially gaining access to sensitive enterprise data and systems that the compromised user has authorization to access. The attack vector requires local privilege access on the client machine, which aligns with ATT&CK technique T1078.004 for valid accounts and T1566.001 for spearphishing attachments that might lead to local compromise. Once the attacker obtains the password equivalent, they can establish connections to the SAP backend systems using legitimate user credentials, potentially escalating privileges or accessing restricted data depending on the user's authorization levels within the SAP environment. This creates a significant risk for organizations where SAP GUI clients are used across multiple departments and business units, as the compromise of a single client could potentially provide access to critical enterprise resources.
Organizations should immediately implement mitigation strategies focusing on patch management and access control measures to address this vulnerability. The primary remediation involves upgrading SAP GUI for Windows to versions 7.60 PL13 or 7.70 PL4, which contain the necessary security fixes to prevent credential leakage. Additionally, organizations should enforce strict local access controls and implement monitoring for suspicious activities on client machines that might indicate credential harvesting attempts. Network segmentation and privileged access management controls should be reinforced to limit the potential impact of credential compromise, while security awareness training should be enhanced to prevent social engineering attacks that might lead to local system compromise. The vulnerability also highlights the importance of implementing proper application hardening practices and conducting regular security assessments of client-side applications to identify and remediate similar information disclosure flaws before they can be exploited by threat actors.