CVE-2016-2564
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 · uneditedInvision Power Services (IPS) Community Suite before 4.1.9 makes session hijack easier by relying on the PHP uniqid function without the more_entropy flag. Attackers can guess an Invision Power Board session cookie if they can predict the exact time of cookie generation.
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 · high confidenceThe IPS Community Suite before 4.1.9 uses PHP's uniqid() function without the more_entropy flag for session cookie generation. This makes session IDs predictable because uniqid() derives its output from system time (microseconds) with insufficient randomization, allowing attackers who can determine the approximate cookie generation time to brute-force or guess valid session identifiers.
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<= 4.1.8.1CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/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 checksWork through these to decide whether this CVE applies to you.
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Locate the installed IPS Community Suite versionAccess the Admin Control Panel and navigate to System > Overview, or inspect the /applications/core/sources/Application/Application.php file for the version constant, or check the footer of the front-end for the version displayAffected if The displayed version is 4.1.8.1 or lower (any version <= 4.1.8.1)
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Confirm the session cookie mechanism is activeLog into the community forum and inspect browser cookies for a session cookie (typically named ips_member_id or similar session identifier). Use browser developer tools or command-line tools like curl to verify cookies are returned after authenticationAffected if Session cookies are being generated and used by the application
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Verify session ID format matches the vulnerable uniqid patternExamine a valid session cookie value. The vulnerable implementation uses uniqid() which produces a 13-character hexadecimal string based on microseconds. Compare your session ID format against this patternAffected if Session IDs are 13-character hex strings derived from microsecond-based generation (without more_entropy)
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Cross-reference with the affected version rangeDocument the exact version found in step 1. The vulnerability exists only in versions 4.1.8.1 and below. Versions 4.1.9 and later include the more_entropy flag which adds additional randomizationAffected if The installed version is 4.1.8.1 or any earlier 4.x release
You are affected if the installed IPS Community Suite version is 4.1.8.1 or lower AND the application is generating session cookies, since earlier versions use predictable uniqid() output without sufficient entropy for session ID generation.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade to IPS Community Suite 4.1.9 or later, which addresses the uniqid predictability issue. If immediate upgrade is not feasible, implement additional session security controls such as IP binding, User-Agent validation, and shorter session timeouts.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-2564 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2016-2564 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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