CVE-2021-20110
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 · uneditedDue to Manage Engine Asset Explorer Agent 1.0.34 not validating HTTPS certificates, an attacker on the network can statically configure their IP address to match the Asset Explorer's Server IP address. This will allow an attacker to send a NEWSCAN request to a listening agent on the network as well as receive the agent's HTTP request verifying its authtoken. In httphandler.cpp, the agent reaching out over HTTP is vulnerable to an Integer Overflow, which can be turned into a Heap Overflow allowing for remote code execution as NT AUTHORITY/SYSTEM on the agent machine. The Integer Overflow occurs when receiving POST response from the Manage Engine server, and the agent calling "HttpQueryInfoW" in order to get the "Content-Length" size from the incoming POST request. This size is taken, but multiplied to a larger amount. If an attacker specifies a Content-Length size of 1073741823 or larger, this integer arithmetic will wrap the value back around to smaller integer, then calls "calloc" with this size to allocate memory. The following API "InternetReadFile" will copy the POST data into this buffer, which will be too small for the contents, and cause heap overflow.
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 confidenceManage Engine Asset Explorer Agent 1.0.34 fails to validate HTTPS certificates, allowing an attacker to spoof the server IP and send malicious NEWSCAN requests. The agent is vulnerable to an integer overflow in httphandler.cpp when processing the Content-Length header from POST responses. When Content-Length is 1073741823 or larger, the integer arithmetic wraps around to a smaller value, causing calloc to allocate an undersized buffer. Subsequent InternetReadFile copies POST data into this too-small buffer, resulting in heap overflow and RCE as NT AUTHORITY/SYSTEM.
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= 1.0.34CVSS 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
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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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Confirm Asset Explorer Agent installationCheck if the program exists in typical installation paths such as C:\Program Files\ManageEngine\AssetExplorer\Agent or C:\ManageEngine\AssetExplorer\Agent. Use dir command or file explorer to verify the agent executable (AgentService.exe or similar) is present.Affected if The Asset Explorer Agent software is installed on the system.
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Identify installed versionRight-click the agent executable (typically named AssetExplorerAgent.exe, AgentService.exe, or similar), select Properties, and check the File Version field. Alternatively, run: wmic product where "name like '%Asset%Explorer%'" get name,versionAffected if The installed version is exactly 1.0.34.
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Verify agent service is runningOpen Services console (services.msc) and look for a service named 'ManageEngine AssetExplorer Agent' or 'Asset Explorer Agent', or run: sc query AssetExplorerAgentAffected if The agent service is installed and running.
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Check if agent listens on network portsRun netstat -an | findstr "LISTENING" and look for ports typically used by the agent (often 3333, 8080, or similar). Also check: netsh firewall show state to see open ports associated with the agent.Affected if The agent is listening on network ports, accepting remote connections.
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Confirm vulnerability trigger conditions presentThe vulnerability requires the agent to receive a POST response with Content-Length header value of 1073741823 (0x3FFFFFFF) or larger. This is typically triggered during a NEWSCAN request from a spoofed server.Affected if The agent processes network requests from remote servers without certificate pinning, and a malicious server could send specially crafted responses.
The system is affected if Zohocorp Manageengine Assetexplorer version 1.0.34 is installed and the agent service is actively running and accepting network connections.
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 dataApply vendor patch for Asset Explorer Agent; until patch available, implement network segmentation and certificate pinning to prevent server spoofing attacks.
- Consultation6.0 h
- Implementation10.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20110 — 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-2021-20110 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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- 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
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