Security readout for executives and security teams
Plain-English summary
Cisco IOS devices before 15.2(1)T may leak memory in the HTTP PROXY Server process under a specific Web Security configuration. The business risk is availability: memory exhaustion could degrade router or security service reliability. The provided sources do not include CVSS scoring or active exploitation evidence.
Executive priority
Treat as a targeted availability risk for legacy Cisco IOS deployments, not a broadly confirmed emergency. Prioritize asset discovery and upgrade planning where the specific Web Security and NTLM configuration exists.
Technical view
CVE-2011-4661 describes Cisco bug CSCtu52820: a memory leak in Cisco IOS HTTP PROXY Server when Cisco ISR Web Security with Cisco ScanSafe and NTLM user authentication is configured. Affected versions are listed as Cisco IOS before 15.2(1)T. The sources do not describe trigger mechanics, indicators, or exploitability details.
Likely exposure
Exposure appears limited to Cisco IOS devices before 15.2(1)T that use Cisco ISR Web Security with Cisco ScanSafe and NTLM authentication. Devices not running that feature combination are not shown as affected by the provided sources.
Exploitation context
The CVE is not listed as KEV in the provided bundle, and no cited source states active exploitation. The source bundle also does not identify public exploit code or detailed attack prerequisites beyond the affected configuration.
Researcher notes
Evidence is sparse: no CVSS, CWE, indicators, or exploitation details are provided. Focus validation on version, feature configuration, and memory behavior. Avoid assuming impact beyond memory leak and service reliability risk.
Mitigation direction
- Inventory Cisco IOS devices running versions before 15.2(1)T.
- Confirm whether ISR Web Security, Cisco ScanSafe, and NTLM authentication are enabled.
- Upgrade to a Cisco fixed or supported IOS release per vendor guidance.
- Monitor HTTP PROXY Server memory until remediation is complete.
- Disable unused affected web-security or NTLM functionality if vendor guidance permits.
Validation and detection
- Check Cisco IOS version on potentially affected routers.
- Review configuration for ISR Web Security, ScanSafe, and NTLM authentication.
- Inspect logs and telemetry for HTTP PROXY Server memory growth.
- Verify remediation against Cisco release notes and internal change records.
- Document non-exposed systems with version and feature evidence.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CVE-2011-4661 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cisco.com/c/en/us/td/docs/ios/15_2m_and_t/release/notes/15_2m_and_t/152-1TCAVS.htmlCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.