Accellion FTA wmProgressstat.html Server-Side Request Forgery (SSRF) Vulnerability (CVE-2021-27103) Analysis and Mitigation Guide
Executive & SecOps Summary
SECOPS ASSESSMENTAccellion FTA 9_12_411 and earlier
Unauthenticated remote attackers can exploit this vulnerability via crafted POST requests to access internal network resources or chain it with other flaws for remote code execution
Immediately upgrade Accellion FTA to version 9_12_416 or later and restrict external access
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Immediately upgrade your Accellion FTA deployment to version 9_12_416 or later to resolve the vulnerability.
# Access the Accellion FTA administrative console and apply the latest security updates
fta_admin --update --version 9_12_4162. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, block external access to the vulnerable endpoint 'wmProgressstat.html' using a Web Application Firewall (WAF) or a reverse proxy configuration.
# Nginx configuration to block access to the vulnerable endpoint
server {
listen 443 ssl;
server_name fta.yourdomain.com;
location ~* /wmProgressstat\.html {
deny all;
return 403;
}
}3. Log Audit & IoC Verification Commands
Inspect web server access logs for suspicious POST requests targeting 'wmProgressstat.html' to identify potential exploitation attempts.
# Search access logs for POST requests to the vulnerable endpoint
grep -i 'POST' /var/log/httpd/access_log | grep -i 'wmProgressstat.html'
grep -i 'POST' /var/log/nginx/access.log | grep -i 'wmProgressstat.html'Block Exploits Instantly with Managed Virtual Patching Rules
Can't patch production immediately? Deploy managed WAF rules at the edge to intercept RCE, SQLi, and deserialization payloads before they hit your origin server.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2021-27103) is a critical Server-Side Request Forgery (SSRF) vulnerability residing in the 'wmProgressstat.html' component of Accellion FTA (File Transfer Appliance). The root cause lies in insufficient validation of user-supplied input within HTTP POST requests, allowing remote attackers to coerce the appliance into making unauthorized requests to internal loopback interfaces or backend services.
2. Exploitation Mechanics & Attack Scenario
An unauthenticated attacker sends a specially crafted HTTP POST request targeting 'wmProgressstat.html'. By manipulating specific parameters within the payload, the attacker forces the FTA server to initiate requests to internal services (such as local databases or administrative APIs) that are otherwise inaccessible from the outside. This mechanism is frequently chained with other vulnerabilities to extract database credentials, hijack active sessions, and ultimately achieve full system compromise.
3. Infrastructure & Business Impact
With a CVSS score of 9.8 (Critical), this vulnerability poses an extreme risk and is actively exploited in the wild, as confirmed by its inclusion in the CISA KEV catalog. Successful exploitation can lead to unauthorized access to sensitive files transferred via the appliance, data exfiltration, and lateral movement within the enterprise network.
Official Vendor Advisories & References
Accellion FTA 9_12_411 and earlier is affected by SSRF via a crafted POST request to wmProgressstat.html. The fixed version is FTA_9_12_416 and later.
Frequently Asked SecOps Questions (CVE-2021-27103)
FAQQ1. How critical is CVE-2021-27103 and is it actively exploited in the wild?
CVE-2021-27103 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 11.4%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2021-27103?
Primary impacted vendors include accellion across fta. Scope summary: Accellion FTA versions 9_12_411 and earlier (Fixed in FTA_9_12_416 and later)
Q3. What temporary mitigations or workarounds exist for CVE-2021-27103 before patching?
[Mitigation] Immediately upgrade Accellion FTA to version 9_12_416 or later and restrict external access Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
Generate an Internal Engineering Notice or CISO Report for CVE-2021-27103
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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