Firewall Services ModuleHardware / appliance · Cisco
CVE-2013-1193
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 · uneditedThe Secure Shell (SSH) implementation on Cisco Adaptive Security Appliances (ASA) devices, and in Cisco Firewall Services Module (FWSM), does not properly terminate sessions, which allows remote attackers to cause a denial of service (SSH service outage) by repeatedly establishing SSH connections, aka Bug IDs CSCue63881, CSCuf51892, CSCue78671, and CSCug26937.
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 confidenceThe SSH implementation on Cisco ASA and FWSM devices fails to properly terminate SSH sessions, allowing remote attackers to repeatedly establish new SSH connections until the SSH service becomes unavailable due to resource exhaustion.
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
Firewall Services ModuleHardware / appliance
all versions
Adaptive Security Appliance SoftwareOperating system
all versionsCVSS 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
- None
- Integrity
- None
- Availability
- Partial
AV:N/AC:L/Au:N/C:N/I:N/A:P
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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Identify the device modelRun 'show version' or 'show inventory' to confirm the device is a Cisco ASA or Firewall Services Module (FWSM)Affected if The device is a Cisco ASA or FWSM appliance (all versions of both are affected)
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Check if SSH is enabledRun 'show ssh' to display SSH server configuration and active sessionsAffected if SSH is enabled and the device is an affected model (all versions are vulnerable when SSH is running)
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Review active SSH connection countRun 'show ssh' and compare the number of active sessions to expected baseline; also run 'show processes cpu history' to check for elevated CPUAffected if There are an unusually high number of SSH connections or CPU spikes correlating with SSH activity
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Inspect SSH management access control listsRun 'show run all ssh' or examine the running configuration for 'ssh' commands with ACL definitions to see if source IP restrictions are appliedAffected if SSH management access is open to any source (0.0.0.0/0) or not explicitly restricted to trusted IPs
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Check connection rate limiting configurationRun 'show run | include rate-limit' or examine class maps and policy maps for connection rate limits on SSH trafficAffected if No rate limiting or connection limits are configured for SSH traffic
The environment is affected if SSH is enabled on a Cisco ASA or FWSM device, regardless of version, especially if the device is exposed to untrusted networks without IP-based access restrictions or rate limiting.
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 dataRestrict SSH management access to trusted IP addresses via ACLs, implement connection rate limiting, and apply the Cisco security update once available.
Fix this in Firewall Services Module
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2013-1193 — 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-2013-1193 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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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.
- 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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