FatPipe WARP, IPVPN, MPVPN Web Management Interface Arbitrary File Upload and Remote Code Execution (CVE-2021-27860)
Executive & SecOps Summary
SECOPS ASSESSMENTFatPipe WARP, IPVPN, and MPVPN software prior to versions 10.1.2r60p92 and 10.2.2r44p1
A remote, unauthenticated attacker can upload arbitrary files to any location on the filesystem, potentially leading to remote code execution with system privileges
Immediately upgrade to patched versions (10.1.2r60p92, 10.2.2r44p1 or later) and restrict external access to the web management interface
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Apply the official security patches provided by the vendor immediately to mitigate this active threat. Verify your current version and upgrade to the patched releases.
# Access the FatPipe CLI to check the current running software version
show version
# Follow the vendor-specific upgrade procedure to apply the secure firmware image
# (Ensure target version is 10.1.2r60p92, 10.2.2r44p1, or higher)2. Temporary Workaround & Hardening Configuration
If patching cannot be applied immediately, restrict access to the web management interface. Disable external WAN-side access and restrict management access to trusted internal IP addresses only.
# Example: Block external access to web management ports (80/443) on the WAN interface
iptables -A INPUT -p tcp -i eth0 --dport 443 -j DROP
# Example: Allow access only from a trusted management subnet (e.g., 192.168.10.0/24)
iptables -I INPUT -p tcp -s 192.168.10.0/24 --dport 443 -j ACCEPT3. Log Audit & IoC Verification Commands
Inspect web server logs and system directories for indicators of compromise (IoCs) such as unauthorized file uploads or directory traversal attempts.
# Scan web server access logs for suspicious POST requests containing directory traversal sequences
grep -Ei 'POST' /var/log/httpd/access_log | grep -E '\.\./'
# Search for recently created or modified script files in the web root directory ind /var/www/html/ -mtime -30 -type f \( -name '*.php' -o -name '*.cgi' -o -name '*.sh' \)Stop Exposing VPN Ports to the Internet — Switch to Zero-Trust Access
Eliminate public-facing VPN concentrators and firewall management ports with identity-first Zero-Trust Network Access.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2021-27860, FPSA006) is a critical arbitrary file upload flaw (CWE-434) residing in the web management interface of FatPipe WARP, IPVPN, and MPVPN appliances. The root cause is the lack of proper validation and sanitization of user-supplied file paths and filenames during upload operations. This allows unauthenticated remote attackers to bypass directory restrictions and write arbitrary files anywhere on the local filesystem.
2. Exploitation Mechanics & Attack Scenario
An attacker can exploit this vulnerability by sending a specially crafted HTTP POST request containing directory traversal sequences (e.g., '../../') in the filename parameter to the file upload endpoint. By leveraging this path traversal, the attacker can place malicious files, such as web shells or executable binaries, into web-accessible directories or system startup paths. Once uploaded, the attacker can trigger execution by directly requesting the file, achieving unauthenticated remote code execution (RCE).
3. Infrastructure & Business Impact
FatPipe appliances serve as critical edge infrastructure for WAN optimization and VPN gateway services. Because this vulnerability is actively exploited in the wild and listed in the CISA KEV catalog, it poses an immediate threat. Successful exploitation grants full administrative control over the gateway, enabling threat actors to intercept network traffic, pivot laterally into the internal corporate network, compromise VPN sessions, or deploy ransomware.
Official Vendor Advisories & References
A vulnerability in the web management interface of FatPipe WARP, IPVPN, and MPVPN software prior to versions 10.1.2r60p92 and 10.2.2r44p1 allows a remote, unauthenticated attacker to upload a file to any location on the filesystem. The FatPipe advisory identifier for this vulnerability is FPSA006.
Frequently Asked SecOps Questions (CVE-2021-27860)
FAQQ1. How critical is CVE-2021-27860 and is it actively exploited in the wild?
CVE-2021-27860 is rated CVSS 8.8 (HIGH) with a 30-day EPSS exploitation probability of 39.7%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2021-27860?
Primary impacted vendors include fatpipe across warp, ipvpn, mpvpn. Scope summary: All FatPipe WARP, IPVPN, and MPVPN software versions prior to 10.1.2r60p92 and 10.2.2r44p1
Q3. What temporary mitigations or workarounds exist for CVE-2021-27860 before patching?
[Mitigation] Immediately upgrade to patched versions (10.1.2r60p92, 10.2.2r44p1 or later) and restrict external access to the web management interface 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-2021-27860
Instantly format this advisory into an executive CISO summary or engineering patch ticket.
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