Authentication bypass via unchecked DCERPC pointer arithmetic
Published Jun 22, 2023 · Updated Feb 13, 2025
Out-of-bounds pointer use in VMware vCenter Server 7.0 and 8.0 allows remote attackers to bypass authentication via DCERPC. The save_sec_fragment function derives an authentication-trailer pointer from attacker-controlled fragment and authentication lengths without bounds checks, then copies from it into the authentication buffer. Network access to the DCERPC service is sufficient; crafted packets corrupt Kerberos authentication input, while public sources do not demonstrate post-bypass actions.
Summary
What happened
Out-of-bounds pointer use in VMware vCenter Server 7.0 and 8.0 allows remote attackers to bypass authentication via DCERPC. The save_sec_fragment function derives an authentication-trailer pointer from attacker-controlled fragment and authentication lengths without bounds checks, then copies from it into the authentication buffer. Network access to the DCERPC service is sufficient; crafted packets corrupt Kerberos authentication input, while public sources do not demonstrate post-bypass actions.
The record
- CVE
- CVE-2023-20895
- Published
- Jun 22, 2023
- Updated
- Feb 13, 2025
- Vendor
- VMware
- Product
- VMware vCenter Server
- Classifications
- CWE-823, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 22, 2023CVE publishedPublication date reported by the CVE source.
- Feb 13, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=7.0 <7.0 u3m
- Affected versionversion=8.0 <8.0 U1b
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo