Zook AgentApplication · Mastersoft

CVE-2020-7877

HIGH · 8.8 CVSS v3.1 Published 2021-09-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
A buffer overflow issue was discovered in ZOOK solution(remote administration tool) through processing 'ConnectMe' command while parsing a crafted OUTERIP value because of missing boundary check. This vulnerability allows the attacker to execute remote arbitrary command.

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

A buffer overflow vulnerability exists in ZOOK solution (remote administration tool) due to missing boundary checks when parsing the OUTERIP value during 'ConnectMe' command processing. The lack of input length validation on the OUTERIP parameter allows attackers to overflow the buffer and execute arbitrary commands remotely.

MitigationImplement strict input validation and boundary checking on the OUTERIP parameter before buffer operations. If available, apply vendor patches; otherwise, refactor the parsing logic to enforce maximum length limits and use safe string handling functions.

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
Zook AgentApplication
Affected:= 2.0.6.1
Zook ViewerApplication
Affected:= 2.0.4.6

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
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/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 checks

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

  1. Verify Zook software installation
    Check system for installed Mastersoft Zook Agent or Zook Viewer applications by reviewing installed programs list or searching for Zook-related executables and directories
    Affected if Neither Zook Agent nor Zook Viewer is installed, then not affected
  2. Identify installed Zook version
    Locate the installed Zook application and determine its exact version number (typically found in program properties, about dialog, or version info of the executable)
    Affected if Version is 2.0.6.1 for Zook Agent or 2.0.4.6 for Zook Viewer exactly
  3. Confirm ConnectMe feature availability
    Verify that the ConnectMe command functionality is present and accessible in the installed Zook application
    Affected if ConnectMe feature is present and can process the OUTERIP parameter
  4. Assess network exposure of Zook service
    Determine if the Zook service is listening on network ports and accessible from external sources (review firewall rules and service binding configuration)
    Affected if Service is network-accessible and accepts ConnectMe commands with OUTERIP parameter

Affected only if Zook Agent version 2.0.6.1 or Zook Viewer version 2.0.4.6 is installed AND the ConnectMe command with OUTERIP parameter is available and accessible on the system or network

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

Implement strict input validation and boundary checking on the OUTERIP parameter before buffer operations. If available, apply vendor patches; otherwise, refactor the parsing logic to enforce maximum length limits and use safe string handling functions.

Fix this in Zook Agent Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,000
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,800.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-7877 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-7877 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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