CVE-2017-14511 in E-Recruiting
Summary
by MITRE
An issue was discovered in SAP E-Recruiting (aka ERECRUIT) 605 through 617. When an external applicant registers to the E-Recruiting application, he/she receives a link by email to confirm access to the provided email address. However, this measure can be bypassed and attackers can register and confirm email addresses that they do not have access to (candidate_hrobject is predictable and corr_act_guid is improperly validated). Furthermore, since an email address can be registered only once, an attacker could prevent other legitimate users from registering. This is SAP Security Note 2507798.
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Analysis
by VulDB Data Team • 11/17/2019
The vulnerability identified in CVE-2017-14511 affects SAP E-Recruiting versions 605 through 617, representing a critical authorization and access control flaw that undermines the application's email verification mechanism. This weakness stems from predictable identifier generation and insufficient input validation, creating a pathway for unauthorized users to manipulate the registration process. The vulnerability directly impacts the integrity of the candidate registration system by allowing attackers to register email addresses they do not control, effectively compromising the application's user authentication and access management framework.
The technical root cause of this vulnerability lies in the predictable nature of the candidate_hrobject parameter and the improper validation of the corr_act_guid field during the email confirmation process. When external applicants initiate registration, the system generates a confirmation link containing these identifiers that should serve as unique access tokens. However, the predictability of candidate_hrobject allows attackers to generate valid confirmation tokens for arbitrary email addresses without legitimate access to those addresses. The corr_act_guid parameter validation fails to properly verify the authenticity of the confirmation request, enabling attackers to bypass the email verification step entirely.
This vulnerability creates significant operational impact by enabling account takeover and denial of service attacks against legitimate users. An attacker can register any email address they choose and subsequently confirm it, effectively gaining unauthorized access to that email address's account within the E-Recruiting system. The restriction that prevents duplicate email registrations becomes a weapon for attackers to block legitimate users from accessing the system entirely, creating a form of service disruption that affects the organization's recruitment processes. The vulnerability also undermines the principle of least privilege by allowing unauthorized individuals to assume the identity of legitimate candidates.
The security implications extend beyond simple unauthorized access to encompass broader system integrity concerns. This flaw aligns with CWE-284 (Improper Access Control) and CWE-352 (Cross-Site Request Forgery) categories, as it represents a failure in access control validation and potentially enables CSRF-like attacks through predictable identifier manipulation. From an ATT&CK framework perspective, this vulnerability maps to T1078 (Valid Accounts) and T1499 (Endpoint Denial of Service) techniques, as attackers can leverage valid-looking accounts to gain access and simultaneously prevent legitimate users from accessing their own accounts. Organizations using SAP E-Recruiting in production environments face risks of data exposure, recruitment process disruption, and potential compliance violations when this vulnerability remains unaddressed.
Mitigation strategies should focus on implementing proper input validation for all identifiers, eliminating predictability in generated tokens, and enforcing strict email uniqueness checks with proper access controls. SAP recommends applying the security patch referenced in SAP Security Note 2507798, which addresses the validation weaknesses in the confirmation process. Organizations should also implement additional monitoring for unusual registration patterns and consider implementing rate limiting to prevent automated exploitation attempts. The fix should ensure that corr_act_guid parameters are properly validated and that candidate_hrobject values cannot be predicted or generated by unauthorized parties, thereby restoring the intended email verification security controls within the E-Recruiting application.