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Asyncos CVE-2018-0087

MEDIUM
Improper Authentication (CWE-287)
2018-03-08 psirt@cisco.com
5.6
CVSS 3.0 · NVD
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A07:2025 - Authentication Failures
ASVS 5.0
V6 - Authentication Authentication mechanism validation
MITRE ATT&CK

2 techniques across 2 tactics: Defense Evasion, Initial Access

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Impact

CVSS score of 5.6 (MEDIUM). Attack characteristics: network attack vector, high complexity, no privileges required, no user interaction not required.

Exploit ScenarioDerived

A remote attacker could bypass authentication mechanisms to gain unauthorized access by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 1.9% exploitation probability (EPSS)

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AnalysisAI

A vulnerability in the FTP server of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to log in to the FTP server of the device without a valid password. Rated medium severity (CVSS 5.6), this vulnerability is remotely exploitable, no authentication required. No vendor patch available.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Implement multi-factor authentication, enforce strong password policies, use proven authentication frameworks.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Improper Authentication (CWE-287), which allows attackers to bypass authentication mechanisms to gain unauthorized access. A vulnerability in the FTP server of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to log in to the FTP server of the device without a valid password. The attacker does need to have a valid username. The vulnerability is due to incorrect FTP user credential validation. An attacker could exploit this vulnerability by using FTP to connect to the management IP address of the targeted device. A successful exploit could allow the attacker to log in to the FTP server of the Cisco WSA without having a valid password. This vulnerability affects Cisco AsyncOS for WSA Software on both virtual and hardware appliances that are running any release of Cisco AsyncOS 10.5.1 for WSA Software. The device is vulnerable only if FTP is enabled on the management interface. FTP is disabled by default. Cisco Bug IDs: CSCvf74281. Affected products include: Cisco Asyncos.

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  • Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 5.6 MEDIUM
AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

DescriptionNVD

A vulnerability in the FTP server of the Cisco Web Security Appliance (WSA) could allow an unauthenticated, remote attacker to log in to the FTP server of the device without a valid password. The attacker does need to have a valid username. The vulnerability is due to incorrect FTP user credential validation. An attacker could exploit this vulnerability by using FTP to connect to the management IP address of the targeted device. A successful exploit could allow the attacker to log in to the FTP server of the Cisco WSA without having a valid password. This vulnerability affects Cisco AsyncOS for WSA Software on both virtual and hardware appliances that are running any release of Cisco AsyncOS 10.5.1 for WSA Software. The device is vulnerable only if FTP is enabled on the management interface. FTP is disabled by default. Cisco Bug IDs: CSCvf74281.

Threat Intelligence Overview

EPSS Score
1.9%
Top 23% exploitable
Data Quality
2 sources
Confidence: Low

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 1.9%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
Medium

Priority Score

30
Low Medium High Critical
KEV: 0
EPSS: +2
CVSS: +28
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)NVD

cpe:2.3:o:cisco:asyncos:10.5.1-296:*:*:*:*:*:*:*
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A vulnerability in the web-based management interface of Cisco Email Security Appliance, Cisco Secure Email and Web Mana

CVE-2021-1359 HIGH
8.8 Jul 08

A vulnerability in the configuration management of Cisco AsyncOS for Cisco Web Security Appliance (WSA) could allow an a

CVE-2019-15956 HIGH
8.8 Nov 26

A vulnerability in the web management interface of Cisco AsyncOS Software for Cisco Web Security Appliance (WSA) could a

CVE-2019-1886 HIGH
8.6 Jul 04

A vulnerability in the HTTPS decryption feature of Cisco Web Security Appliance (WSA) could allow an unauthenticated, re

CVE-2024-20383 HIGH
8.4 May 15

A vulnerability in the web-based management interface of Cisco AsyncOS Software for Cisco Secure Email and Web Manager c

CVE-2024-20435 HIGH
7.8 Jul 17

A vulnerability in the CLI of Cisco AsyncOS for Secure Web Appliance could allow an authenticated, local attacker to exe

CVE-2020-3367 HIGH
7.8 Nov 18

A vulnerability in the log subscription subsystem of Cisco AsyncOS for the Cisco Secure Web Appliance (formerly Web Secu

CVE-2018-0095 HIGH
7.8 Jan 18

A vulnerability in the administrative shell of Cisco AsyncOS on Cisco Email Security Appliance (ESA) and Content Securit

CVE-2016-1461 HIGH
7.5 Aug 01

Cisco AsyncOS on Email Security Appliance (ESA) devices through 9.7.0-125 allows remote attackers to bypass malware dete

CVE-2016-1438 HIGH
7.5 Jun 23

Cisco AsyncOS 9.7.0-125 on Email Security Appliance (ESA) devices allows remote attackers to bypass intended spam filter

CVE-2022-20653 HIGH
7.5 Feb 17

A vulnerability in the DNS-based Authentication of Named Entities (DANE) email verification component of Cisco AsyncOS S

CVE-2021-34741 HIGH
7.5 Nov 04

A vulnerability in the email scanning algorithm of Cisco AsyncOS software for Cisco Email Security Appliance (ESA) could

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