Home/CVE/A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA)
CVE

CVE-2021-1534

A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA)

A vulnerability in the antispam protection mechanisms of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to bypass the URL reputation filters on an affected device. This vulnerability is due to improper processing of URLs. An attacker could exploit this vulnerability by crafting a URL in a particular way.

A successful exploit could allow the attacker to bypass the URL reputation filters that are configured for an affected device, which could allow malicious URLs to pass through the device.

MEDIUM · CVSS 5.8 EPSS 0.00279
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-20Improper Input Validation
▤

Affected Products & Versions

1
cisco asyncos< 14.0.1
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Scoring & Timeline

5.8
MEDIUM · CVSS v3.1 · psirt@cisco.com
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD06 Oct 2021 · 08:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
total
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

1
cisco-csafcisco-sa-esa-url-bypass-sGcfsDrp
🔗

References & Sources

1
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-url-bypass-sGcfsDrpVendor Advisory
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