CVE-2020-3259 — Adaptive Security Appliance Software
HIGHCVE-2020-3259 is a high-severity (CVSS 7.5) Information Exposure vulnerability in cisco adaptive security appliance software. It is in CISA's Known Exploited Vulnerabilities catalog (added 2024-02-15) and has been used in ransomware campaigns — treat it as actively exploited and patch now. A fix is available — see the affected versions and patch details below.
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2024-02-15 — including use in ransomware campaigns. Federal agencies were required to remediate by 2024-03-07.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2020-3259.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2020-3259 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the 50–90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to retrieve memory contents on an affected device, which could lead to the disclosure of confidential information. The vulnerability is due to a buffer tracking issue when the software parses invalid URLs that are requested from the web services interface. An attacker could exploit this vulnerability by sending a crafted GET request to the web services interface. A successful exploit could allow the attacker to retrieve memory contents, which could lead to the disclosure of confidential information. Note: This vulnerability affects only specific AnyConnect and WebVPN configurations. For more information, see the Vulnerable Products section.
Affected Products
adaptive security appliance softwareciscosecure firewall threat defenseciscoResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every cisco adaptive security appliance software deployment and check each version against the affected-products list above.
Fix
Apply the cisco adaptive security appliance software security patch or hotfix for CVE-2020-3259 on the affected version, following the vendor advisory for your exact build.
Workarounds
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
Frequently Asked Questions
Is CVE-2020-3259 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.