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iOSOperating system · Cisco

CVE-2002-1357

HIGH · 10.0 CVSS v2.0 Published 2002-12-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
Multiple SSH2 servers and clients do not properly handle packets or data elements with incorrect length specifiers, which may allow remote attackers to cause a denial of service or possibly execute arbitrary code, as demonstrated by the SSHredder SSH protocol test suite.

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 confidence

This CVE affects multiple SSH2 server and client implementations that fail to properly validate or handle packets and data elements with incorrect length specifiers. When a malformed packet with invalid length fields is received, it can cause the SSH implementation to crash (denial of service) or potentially execute arbitrary code due to buffer handling errors. The vulnerability was discovered using the SSHredder SSH protocol test suite, which specifically tests boundary conditions and malformed input.

MitigationOrganizations should update all SSH server and client implementations to versions that include patches for this vulnerability (post-2002 releases). For legacy systems, consider network-level filtering of malformed SSH packets or upgrading to current, supported SSH implementations.

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
iOSOperating system
Affected:= 12.0s= 12.0st= 12.1e= 12.1ea= 12.1t= 12.2= 12.2s= 12.2t
Ssh ClientApplication
Affected:= 1.0a_for_windows
SecurenettermApplication
Affected:= 5.4.1
Shellguard SshApplication
Affected:= 3.4.6
SecureshellApplication
Affected:= 2.0
PuttyApplication
Affected:= 0.48= 0.49= 0.53
WinscpApplication
Affected:= 2.0.0

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
Complete
Integrity
Complete
Availability
Complete

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

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 SSH client or server software
    On Windows, check Add/Remove Programs or the program's About/Help section. On Cisco iOS, use 'show version' command. Look for any of these products: Cisco iOS, Fissh Ssh Client, Intersoft Securenetterm, Netcomposite Shellguard Ssh, Pragma Systems Secureshell, Putty, or Winscp.
    Affected if Any of the listed products are installed
  2. Determine exact version of Cisco iOS
    If Cisco iOS is in use, use the command 'show version' to identify the exact iOS version. Look for versions matching: 12.0s, 12.0st, 12.1e, 12.1ea, 12.1t, 12.2, 12.2s, or 12.2t.
    Affected if The iOS version exactly matches one of the listed affected versions
  3. Determine exact version of Putty
    Run Putty and check the About section, or run 'putty.exe -V' if supported, or check the executable file properties. Look for versions: 0.48, 0.49, or 0.53.
    Affected if Putty version is exactly 0.48, 0.49, or 0.53
  4. Determine exact version of Winscp
    Check the application About dialog or check the installed program version. Look for version 2.0.0.
    Affected if Winscp version is exactly 2.0.0
  5. Determine version of other listed SSH products
    For Fissh Ssh Client, Intersoft Securenetterm, Netcomposite Shellguard Ssh, or Pragma Systems Secureshell, check their About/Help menus or Add/Remove Programs for version 1.0a_for_windows, 5.4.1, 3.4.6, or 2.0 respectively.
    Affected if Any of these products match their exact affected version (1.0a_for_windows, 5.4.1, 3.4.6, or 2.0)

You are affected if any SSH client or server from the list is installed and its version exactly matches one of the affected versions specified.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Organizations should update all SSH server and client implementations to versions that include patches for this vulnerability (post-2002 releases). For legacy systems, consider network-level filtering of malformed SSH packets or upgrading to current, supported SSH implementations.

Recommended fix High confidence

Upgrade to current versions of each product: PuTTY 0.80+, WinSCP 6.x, and contact Cisco for supported iOS upgrade path. For SecureNetTerm, Shellguard SSH, SecureShell, and SSH Client 1.0a_for_windows - these products are obsolete; replace with maintained SSH solutions.

  1. Identify all affected SSH clients and servers in your environment from the list: Putty (versions 0.48, 0.49, 0.53), WinSCP (version 2.0.0), SecureNetTerm (5.4.1), Shellguard SSH (3.4.6), SecureShell (2.0), SSH Client (1.0a_for_windows), and Cisco iOS (12.0s, 12.0st, 12.1e, 12.1ea)
  2. Remove or decommission all instances of these vulnerable SSH products
  3. Replace deprecated SSH clients (Putty, WinSCP) with current maintained alternatives such as PuTTY 0.80+, WinSCP 6.x, or native OpenSSH clients
  4. For Cisco iOS devices, upgrade to a Cisco IOS version that is still supported by Cisco's security advisories; contact Cisco for appropriate upgrade path to a supported release
  5. If any of these products are embedded in legacy systems that cannot be upgraded, isolate them behind firewalls and restrict network access to minimize exposure
  6. Verify that all SSH implementations are patched against this and other known vulnerabilities using up-to-date security scanning
Caveat Legacy SSH client configurations may need to be migrated to new software. Very old Cisco iOS devices may have hardware limitations preventing upgrade to supported versions and may require replacement.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in iOS Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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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-2002-1357 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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