CVE-2008-4250: Microsoft Windows Buffer Overflow Vulnerability
Microsoft Windows contains a buffer overflow vulnerability in the Windows Server Service that allows remote attackers to execute arbitrary code via a crafted RPC request that triggers an overflow during path canonicalization.
Overview
The Windows Server service contains a stack buffer overflow in its RPC request handler that is triggered during path canonicalization. An unauthenticated remote attacker can send a specially crafted RPC message over SMB ports to execute arbitrary code with SYSTEM privileges, taking full control of the target machine. Affected systems span Windows 2000, XP, Server 2003, Vista, and Server 2008. On Windows 2000, XP, and Server 2003, no authentication is required, and the flaw is considered wormable. The Gimmiv.A malware and the Conficker worm both exploited this vulnerability in the wild.
Vulnerability details
The Windows Server service exposes RPC functionality over SMB (ports 139/tcp and 445/tcp) and is enabled by default on affected Windows versions. During processing of an RPC request, the service performs path canonicalization on caller-supplied path data without properly validating the length of that input. This allows a caller-controlled string to overflow a fixed-size stack buffer (CWE-119), overwriting the return address or other control-flow data on the stack. Because the overflow occurs before any authentication check is applied on Windows 2000, XP, and Server 2003, no credentials are needed to reach the vulnerable code path.
An attacker sends a single crafted RPC message containing a malformed path argument to port 139 or 445 on a reachable target. The oversized path data overflows the stack buffer, redirecting execution to attacker-supplied shellcode (CWE-94). Because the Server service runs as SYSTEM, successful exploitation yields full operating-system control with no prior foothold required. The Microsoft advisory notes the flaw is suitable for a wormable exploit, and active exploitation by Gimmiv.A and Conficker confirmed that assessment. On Vista and Server 2008 the severity rating is lower, suggesting reduced exploitability, though the facts do not specify an explicit authentication requirement for those versions.
Severity and impact
Exploitation status
This vulnerability is confirmed as actively exploited in the wild — it is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog.
Detection and monitoring
- Monitor for unexpected inbound connections to TCP ports 139 and 445 from external or untrusted network segments, particularly from sources with no prior authenticated session, which distinguishes exploit traffic from normal SMB file-sharing activity.
- Look for the svchost.exe or services.exe process spawning unexpected child processes (cmd.exe, powershell.exe, or unknown binaries) immediately after receiving RPC traffic, a pattern consistent with post-overflow shellcode execution under SYSTEM context.
- Audit Windows Security event logs for SYSTEM-level process creation events that lack a corresponding interactive or service logon event, which can indicate code execution injected through the Server service rather than a legitimate session.
Remediation
Additional hardening
- Apply Microsoft Security Bulletin MS08-067 (update 958644) to all affected systems. Windows 2000, XP, and Server 2003 are rated Critical; Vista and Server 2008 are rated Important. Consult the vendor advisory listed in References for download details.
- Block inbound access to TCP ports 139 and 445 at the network perimeter and on host-based firewalls for all systems that do not require external SMB access, removing the attack surface entirely for internet-sourced exploitation.
- Segment internal networks so that workstations and servers cannot reach each other's SMB ports without a business need, limiting lateral movement in the event a single host is compromised through this or a similar wormable flaw.
- Disable the Windows Server service on hosts that do not require file, print, or named-pipe sharing, reducing the number of systems exposing the vulnerable RPC handler.
Key dates
References
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2008/ms08-067
- https://learn.microsoft.com/en-us/security-updates/securitybulletins/2008/ms08-067
- https://nvd.nist.gov/vuln/detail/CVE-2008-4250
- http://www.kb.cert.org/vuls/id/827267
- http://secunia.com/advisories/32326
- http://www.securityfocus.com/bid/31874
- http://blogs.securiteam.com/index.php/archives/1150
- http://marc.info/?l=bugtraq&m=122703006921213&w=2
Frequently asked questions
Does CVE-2008-4250 affect my FedRAMP authorization?
If Microsoft Windows runs inside your authorization boundary, yes. CVE-2008-4250 appears in CISA's Known Exploited Vulnerabilities (KEV) catalog, and its remediation deadline of June 3, 2026 has already passed. For a FedRAMP-authorized service, an unpatched KEV in your boundary is a finding your assessor and sponsoring agency can see now. At this point, you either close the gap or formally document the mitigation and the delay.
How does Knox help me handle CVE-2008-4250?
Knox does not patch your software. Remediating Microsoft Windows is your responsibility under the FedRAMP shared-responsibility model. What Knox provides is the pre-authorized, single-tenant boundary to remediate within, plus continuous compliance monitoring and audit-artifact coverage to document the fix for your next assessment. Applying the patch is yours to own; maintaining a defensible compliance posture while you do it is not something you have to manage alone.
How does Knox's monitoring help with vulnerabilities like this?
Knox's automated continuous monitoring platform watches your environment for newly disclosed vulnerabilities and compliance issues on an ongoing basis. For a CVE like CVE-2008-4250, that means exposure surfaces during routine monitoring rather than only when an assessor flags it at review time, giving you earlier visibility and more time to act.
How do I get FedRAMP authorized with Knox?
Knox runs a FedRAMP-as-a-Service platform. It gives SaaS vendors a pre-authorized cloud boundary on AWS, Azure, and GCP. Your application inherits 60-80% of the required security controls. You reach FedRAMP authorization in about 90 days for roughly 90% less than the traditional $3.5M path. Book a meeting and Knox will map your path to authorization.
CVE-2008-4250's remediation deadline of June 3, 2026 has passed. What happens now?
An unremediated CVE-2008-4250 is already a Plan of Action and Milestones (POA&M) item, and a growing POA&M list is what turns a routine continuous-monitoring review into a difficult conversation with your sponsoring agency. Closing it out and documenting why the deadline was missed is what keeps your authorization clean and the agency relationship intact.
Ready to achieve FedRAMP authorization in 90 days or less?
Schedule a meeting to discuss scope, parse readiness, and map your company’s accelerated path to FedRAMP authorization.
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