Cisco Webex Meetings Desktop App for Windows Arbitrary File Overwrite Vulnerability
Cisco · Cisco Webex Meetings
A vulnerability in Cisco Webex Meetings Desktop App for Windows could allow an unauthenticated, remote attacker to overwrite arbitrary files on an end-user system. The vulnerability is due to improper validation of URL parameters that are sent from a website to the affected application. An attacker could exploit this vulnerability by persuading a user to follow a URL to a website that is designed to submit crafted input to the affected application. A successful exploit could allow the attacker to overwrite arbitrary files on the affected system, possibly corrupting or deleting critical system files.
- Exploited
- Not confirmed
- Reports
- 0
- Tactics
- 3/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
Disclosed on 26 Aug 2020. No public exploit code or confirmed exploitation is recorded.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
3 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order 3Initial AccessTA0001
ExecutionTA0002
ImpactTA0040
Detection
0 rules for this CVE · 59 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2020-3440 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
PhishingT156614 general rules
- CVE-2021-31979 CVE-2021-33771 Exploitscriticaltest
- CVE-2021-31979 CVE-2021-33771 Exploits by Sourgumcriticaltest
- HTML Help HH.EXE Suspicious Child Processhightest
- Okta FastPass Phishing Detectionhightest
- Phishing Pattern ISO in Archivehightest
- Potential Malicious Usage of CloudTrail System Managerhightest
- Suspicious External WebDAV Executionhightest
- Suspicious HH.EXE Executionhightest
Malicious FileT1204.00239 general rules
- Droppers Exploiting CVE-2017-11882criticalstable
- Ursnif Malware C2 URL Patterncriticalstable
- Exploit for CVE-2017-8759criticaltest
- Potential Maze Ransomware Activitycriticaltest
- File With Uncommon Extension Created By An Office Applicationhightest
- Flash Player Update from Suspicious Locationhightest
- GAC DLL Loaded Via Office Applicationshightest
- HackTool - LittleCorporal Generated Maldoc Injectionhightest
Stored Data ManipulationT1565.0016 general rules
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 3 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Spam “Broken Seal” DocuSign-themed Delivery w/Fileless Process Hollowing (Zeppelin/Bloat-A) by msudosos22 Mar 2026
- Spam “Broken Seal” DocuSign-themed Delivery w/Fileless Process Hollowing (Zeppelin/Bloat-A) by msudosos22 Mar 2026
- “Broken Seal” DocuSign-themed Delivery with Fileless Process Hollowing (Zeppelin/Bloat-A)13 Feb 2026