Actively exploited in the wild
CrushFTP Authentication Bypass Vulnerability
CrushFTP - CrushFTP · Listed in the CISA KEV since 2025-04-07. This indicates confirmed attacks in production environments.
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CVE-2025-31161
CriticalCVSS 9.8KEVSummary
CrushFTP 10 before 10.8.4 and 11 before 11.3.1 allows authentication bypass and takeover of the crushadmin account (unless a DMZ proxy instance is used), as exploited in the wild in March and April 2025. The vulnerability is a race condition in the AWS4-HMAC (S3-compatible) authorization method of the HTTP component. The server first verifies user existence via login_user_pass() without password, authenticating the session through HMAC verification. Sending a mangled AWS4-HMAC header stabilizes the attack, causing an index-out-of-bounds error that prevents session cleanup.
Risk Assessment
An attacker can gain full control over the system by taking over the administrator account, potentially leading to complete compromise of data and services.
Recommendation
Immediately upgrade CrushFTP to version 10.8.4 or 11.3.1 and apply security patches. If possible, use a DMZ proxy instance.
Other vulnerabilities in CrushFTP
See all- CVE-2025-54309CriticalActively exploited
CrushFTP 10 before 10.8.5 and 11 before 11.3.4_23, when the DMZ proxy feature is not used, mishandles AS2 validation and consequently allows remote attackers to obtain admin access via HTTPS, as exploited in the wild in July 2025.
- CVE-2017-14035Critical
CrushFTP versions 8.x before 8.2.0 have a serialization vulnerability.
Original NVD description (English source)
CrushFTP 10 before 10.8.4 and 11 before 11.3.1 allows authentication bypass and takeover of the crushadmin account (unless a DMZ proxy instance is used), as exploited in the wild in March and April 2025, aka "Unauthenticated HTTP(S) port access." A race condition exists in the AWS4-HMAC (compatible with S3) authorization method of the HTTP component of the FTP server. The server first verifies the existence of the user by performing a call to login_user_pass() with no password requirement. This will authenticate the session through the HMAC verification process and up until the server checks for user verification once more. The vulnerability can be further stabilized, eliminating the need for successfully triggering a race condition, by sending a mangled AWS4-HMAC header. By providing only the username and a following slash (/), the server will successfully find a username, which triggers the successful anypass authentication process, but the server will fail to find the expected SignedHeaders entry, resulting in an index-out-of-bounds error that stops the code from reaching the session cleanup. Together, these issues make it trivial to authenticate as any known or guessable user (e.g., crushadmin), and can lead to a full compromise of the system by obtaining an administrative account.