CVE-2017-17707 in Password Server
Summary
by MITRE
Due to missing authorization checks, any authenticated user is able to list, upload, or delete attachments to password safe entries in Pleasant Password Server before 7.8.3. To perform those actions on an entry, the user needs to know the corresponding "CredentialId" value, which uniquely identifies a password safe entry. Since "CredentialId" values are implemented as GUIDs, they are hard to guess. However, if for example an entry's owner grants read-only access to a malicious user, the value gets exposed to the malicious user. The same holds true for temporary grants.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 03/11/2020
CVE-2017-17707 represents a critical authorization bypass vulnerability within Pleasant Password Server versions prior to 7.8.3, classified under CWE-863 (Incorrect Authorization) and aligning with ATT&CK technique T1078.101 (Valid Accounts). This vulnerability stems from insufficient access control mechanisms that allow authenticated users to perform unauthorized operations on password safe entries. The flaw specifically affects the attachment management functionality where users can list, upload, or delete attachments without proper authorization checks. The security model relies on CredentialId values as GUIDs to provide uniqueness and prevent guessing attacks, yet this protective measure proves insufficient when legitimate access is granted to malicious actors.
The technical implementation of this vulnerability exposes a fundamental flaw in the server's permission architecture. While CredentialId values are designed as GUIDs to prevent enumeration attacks, the system fails to enforce proper authorization boundaries when users possess legitimate access to entries. When an entry owner grants read-only access to a malicious user, the CredentialId becomes accessible to the attacker, enabling them to manipulate attachments on entries they should not be able to modify. This weakness extends to temporary access grants, where the exposure of CredentialId values creates persistent attack vectors. The vulnerability demonstrates a classic case of insufficient privilege separation where the system does not properly validate whether a user has appropriate permissions for attachment operations, regardless of their access level to the underlying entry.
The operational impact of this vulnerability is significant as it enables unauthorized data manipulation and potential information disclosure. Attackers with access to legitimate entries can exploit this weakness to upload malicious attachments, delete critical files, or enumerate available attachments, potentially leading to data loss or system compromise. The vulnerability affects the integrity and availability of password management data, undermining the core security functions of the password server. Organizations using affected versions face risks of credential theft, data manipulation, and potential lateral movement within their infrastructure, as compromised attachment functionality can serve as a vector for further attacks. The vulnerability's impact is amplified by the fact that it requires minimal reconnaissance to exploit, as CredentialIds are exposed through legitimate access patterns rather than requiring complex enumeration techniques.
Mitigation strategies for CVE-2017-17707 should focus on implementing proper authorization checks for attachment operations. Organizations must upgrade to Pleasant Password Server version 7.8.3 or later where the vulnerability has been addressed through enhanced access control mechanisms. The fix should enforce strict authorization validation for all attachment operations, ensuring that users cannot manipulate attachments without appropriate permissions for the target entry. Additionally, organizations should implement network segmentation and access controls to limit exposure of the password server to unauthorized users. Regular security audits should verify that proper privilege separation exists between different access levels, and monitoring should be implemented to detect unauthorized attachment manipulation attempts. The solution aligns with security best practices outlined in NIST SP 800-53 and ISO 27001, ensuring that access controls are properly enforced for all system operations.