SB2018110907 - Security restrictions bypass in Steam
Published: November 9, 2018
Security Bulletin ID
SB2018110907
CSH Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Security restrictions bypass (CVE-ID: N/A)
CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls
CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a remote authenticated attacker to bypass security restrictions.
The weakness exists in a Steam web API located at partner.steamgames.com/partnercdkeys/assignkeys/ due to attacker can go through all Steam games IDs, as the appid and keyid parameters were easy to guess. A remote authenticated use the
/partnercdkeys/assignkeys/ endpoint on partner.steamgames.com with keycount parameter to "0", bypass the API's limitations, retrieve a file with CD keys belonging to any game and download previously-generated CD keys for a game which they would not normally have access.Remediation
Install update from vendor's website.