Commercial Internet SystemApplication · Microsoft

CVE-1999-0910

MEDIUM · 5.0 CVSS v2.0 Published 1999-09-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
59/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Microsoft Site Server and Commercial Internet System (MCIS) do not set an expiration for a cookie, which could then be cached by a proxy and inadvertently used by a different user.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Microsoft Site Server and Commercial Internet System (MCIS) fail to set an expiration attribute on session cookies, causing them to persist beyond the current session. When these cookies pass through proxy servers, they can be cached and subsequently reused by different users, leading to session hijacking or credential theft.

MitigationConfigure or modify the application to include the 'Expires' attribute on cookies with an appropriate expiration time, or implement proper cache-control headers to prevent proxy caching of authentication cookies.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Commercial Internet SystemApplication
Affected:= 2.0= 2.5
Site ServerApplication
Affected:= 3.0
Site Server CommerceApplication
Affected:= 3.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None

AV:N/AC:L/Au:N/C:P/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Microsoft web product
    Check the installed programs or IIS snap-in for Microsoft Site Server, Microsoft Site Server Commerce, or Microsoft Commercial Internet System. Use 'Add/Remove Programs' or check C:\Inetpub\AdminScripts for site server components.
    Affected if Any of the affected products (MCIS 2.0/2.5, Site Server 3.0, Site Server Commerce 3.0) is installed and serving content.
  2. Inspect HTTP response cookies
    Capture an HTTP response from the server using browser developer tools (Network tab), Fiddler, or curl -I against a page that generates a session cookie. Look at the Set-Cookie header.
    Affected if The Set-Cookie header lacks an 'Expires' or 'Max-Age' attribute, making the cookie a session-only cookie that browsers keep in memory.
  3. Check proxy server cache for cookies
    Examine proxy server logs or cache directories (for Squid, ISA Server, or similar) for stored cookies. Look for files containing session identifiers or authentication tokens.
    Affected if Proxy server is caching cookies from the affected server, which would be visible in cache entries or logs.
  4. Verify browser cookie storage
    Open browser developer tools, go to Application/Storage tab, and examine the stored cookies from the affected domain. Check the 'Expires' column.
    Affected if Cookies from the affected site show no expiration date (session cookie) and are still present after browser restart or in persistent storage beyond the session.

If Microsoft Site Server, Site Server Commerce, or Commercial Internet System (versions 3.0, 2.5, or 2.0) is deployed and HTTP responses contain session cookies without an Expires attribute that can be cached by proxies, the environment is vulnerable to session hijacking via proxy cache reuse.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Configure or modify the application to include the 'Expires' attribute on cookies with an appropriate expiration time, or implement proper cache-control headers to prevent proxy caching of authentication cookies.

Fix this in Commercial Internet System Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing4.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,500
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Scan for this in your stack

Free · runs locally
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-1999-0910 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data