| CVE-2016-4028 | Date: (C)2016-12-16 (M)2023-12-22 |
An issue was discovered in Open-Xchange OX Guard before 2.4.0-rev8. OX Guard uses an authentication token to identify and transfer guest users' credentials. The OX Guard API acts as a padding oracle by responding with different error codes depending on whether the provided token matches the encryption padding. In combination with AES-CBC, this allows attackers to guess the correct padding. Attackers may run brute-forcing attacks on the content of the guest authentication token and discover user credentials. For a practical attack vector, the guest users needs to have logged in, the content of the guest user's "OxReaderID" cookie and the value of the "auth" parameter needs to be known to the attacker.
CVSS Score and Metrics +CVSS Score and Metrics -| CVSS V3 Severity: | CVSS V2 Severity: |
| CVSS Score : 7.5 | CVSS Score : 3.5 |
| Exploit Score: 1.6 | Exploit Score: 6.8 |
| Impact Score: 5.9 | Impact Score: 2.9 |
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| CVSS V3 Metrics: | CVSS V2 Metrics: |
| Attack Vector: NETWORK | Access Vector: NETWORK |
| Attack Complexity: HIGH | Access Complexity: MEDIUM |
| Privileges Required: LOW | Authentication: SINGLE |
| User Interaction: NONE | Confidentiality: PARTIAL |
| Scope: UNCHANGED | Integrity: NONE |
| Confidentiality: HIGH | Availability: NONE |
| Integrity: HIGH | |
| Availability: HIGH | |
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