CVE Vulnerabilities

CVE-2020-8503

Authorization Bypass Through User-Controlled Key

Published: Jan 31, 2020 | Modified: Feb 05, 2020
CVSS 3.x
6.5
MEDIUM
Source:
NVD
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS 2.x
3.5 LOW
AV:N/AC:M/Au:S/C:P/I:N/A:N
RedHat/V2
RedHat/V3
Ubuntu

Biscom Secure File Transfer (SFT) 5.0.1050 through 5.1.1067 and 6.0.1000 through 6.0.1003 allows Insecure Direct Object Reference (IDOR) by an authenticated sender because of an error in a file-upload feature. This is fixed in 5.1.1068 and 6.0.1004.

Weakness

The system’s authorization functionality does not prevent one user from gaining access to another user’s data or record by modifying the key value identifying the data.

Affected Software

Name Vendor Start Version End Version
Secure_file_transfer Biscom 5.0.1050 (including) 5.1.1067 (including)
Secure_file_transfer Biscom 6.0.1000 (including) 6.0.1003 (including)

Extended Description

Retrieval of a user record occurs in the system based on some key value that is under user control. The key would typically identify a user-related record stored in the system and would be used to lookup that record for presentation to the user. It is likely that an attacker would have to be an authenticated user in the system. However, the authorization process would not properly check the data access operation to ensure that the authenticated user performing the operation has sufficient entitlements to perform the requested data access, hence bypassing any other authorization checks present in the system. For example, attackers can look at places where user specific data is retrieved (e.g. search screens) and determine whether the key for the item being looked up is controllable externally. The key may be a hidden field in the HTML form field, might be passed as a URL parameter or as an unencrypted cookie variable, then in each of these cases it will be possible to tamper with the key value. One manifestation of this weakness is when a system uses sequential or otherwise easily-guessable session IDs that would allow one user to easily switch to another user’s session and read/modify their data.

Potential Mitigations

References