CVE-2016-4028
In combination with AES-CBC, this allows attackers to guess the correct padding.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.71%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 0.71% probability · 52th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-255
- Affected
- open-xchange/ox guard
- Source
- cve@mitre.org
References
- http://www.securityfocus.com/archive/1/538732/100/0/threaded
- http://www.securitytracker.com/id/1036154Third Party Advisory, VDB Entry
- http://www.securityfocus.com/archive/1/538732/100/0/threaded
- http://www.securitytracker.com/id/1036154Third Party Advisory, VDB Entry
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.