Hello, I am working on an audit of file operations for a DLP agent. I am trying to implement this mechanism using Endpoint Security. One of the customer's requirements is that write event reports must provide information about the file size both before and after the write operation. The challenge is that the ES_EVENT_TYPE_NOTIFY_WRITE event does not provide information about the changes, and in the stat structure, I see the file's stat prior to the write event. I tried to implement a mechanism based on tracking the sequence of events (open -> write -> close), but it seems macOS does not guarantee such a sequence, as the agent receives ES_EVENT_TYPE_NOTIFY_CLOSE earlier than ES_EVENT_TYPE_NOTIFY_OPEN. Unfortunately, Auth events cannot be used due to no guarantee the DLP agent is the only ES client. Is there any way within the Endpoint Security Framework to guarantee the sequence of NOTIFY events? Are there any other supported (public) APIs or methods besides Endpoint Security to track file system changes? As far as I know, ktrace (which powers fs_usage) is a private framework. Thank you in advance!

Hello, I am working on a DLP solution for macOS using the Endpoint Security framework. I have faced unexpected behavior regarding process identities. Upon receiving an ES_EVENT_TYPE_NOTIFY_EXEC event, my aplication caches the process details for future use by other internal components. This structure stores user identity tokens, including auid, euid, and ruid. However, I noticed that in subsequent ES_EVENT_TYPE_NOTIFY_CLOSE events for the exact same PID, the audit token arrives with a different audit uid, even though no ES_EVENT_TYPE_NOTIFY_EXIT event was triggered for this process. Could you please help me clarify the following questions: In my case the initial value of audit uid is equal to AU_DEFAUDITID. What does it mean? (ES_EVENT_TYPE_NOTIFY_EXEC and ES_EVENT_TYPE_NOTIFY_CLOSE are triggered by a file copy operation in Finder) How is audit uid changing possible? Is there any way to catch it via Endpoint Security? Thank you in advance!

We are developing a DLP agent that uses a NETransparentProxyProvider to perform traffic inspection and modification. Our architecture currently includes: LaunchAgent, which monitors user session activity (login/logout, session activation) Container App, which: installs and activates a System Extension creates and saves the NETransparentProxyManager configuration starts the transparent proxy via startVPNTunnel. We would like to automate the startup of the Transparent Proxy for all users, including newly created users, in a way that is fully supported by macOS. We are looking for official guidance on the correct and supported mechanism for starting a user‑level Network Extension (specifically NETransparentProxyProvider) automatically at user login. Questions: What is the recommended and supported way to automatically start a NETransparentProxyProvider at user login? Are there any constraints or best practices we should follow when designing an automatic startup flow for a Network Extension such as NETransparentProxyProvider? We would appreciate official clarification on the supported deployment patterns for starting a user‑level Transparent Proxy Network Extension automatically in multi‑user enterprise environments.

Hello, I am working on a Launch Daemon (part of a DLP). One of its requirements is to modify PDF files on the fly—specifically, to reduce the page count and truncate the document to meet specific size criteria. I am planning to use the CoreGraphics framework, specifically CGPDFDocumentRef, CGPDFPageRef, and CGDataConsumerRef to rebuild the document in memory and write the modified version. However, since CoreGraphics is historically tied to the graphic subsystem, could you please confirm if the specific PDF-handling subset of CoreGraphics (CGPDFDocument, CGPDFContext) is completely session-independent, memory-safe, and daemon-safe to use from a launch daemon context without any Aqua session? If using CoreGraphics in this context is discouraged, what are the recommended best practices or native alternatives for performing headless PDF modifications within a system daemon on modern macOS? Thank you in advance!

Hello, I am working on network traffic analyser for DLP. The solution is based on NETransparentProxyProvider due to necessity data modifying. To my knowledge, the Transparent Proxy API does not have a concept of an "asynchronous/delayed verdict" for flow authorization. The handleNewFlow(_:) method appears to be invoked sequentially for each new network flow that matches our interception rules. The challenge we are facing is that a portion of our proxy rules and configurations resides in a LaunchDaemon, which the Network Extension communicates with via XPC. Such separation is required by our cross-platform code base. Thus, we are forced to make a synchronous XPC call within handleNewFlow(_:) and block the thread while waiting for the interception verdict from the daemon. This creates a significant bottleneck when establishing new network flows. The current implementation works without issues, but we are always looking for ways to improve performance. Are there any best practices or recommended approaches for parallelizing handleNewFlow(_:)? Thank you in advance.

Hello, I have encountered unexpected behavior when running a Network Extension that implements NETransparentProxyProvider. This extension is part of a DLP (Data Loss Prevention) solution. If the "Auto proxy discovery" option is enabled for the Wi-Fi connection on the managed host, the leaks tool reports memory leaks with the following root cycles: ... 11 (1.03K) ROOT CYCLE: <CFRunLoopSource 0xa430cc540> [192] 10 (864 bytes) ROOT CYCLE: <std::__shared_ptr_emplace<PAC::PACClient> 0xa430f4000> [224] CYCLE BACK TO <CFRunLoopSource 0xa430cc540> [192] 6 (400 bytes) ROOT CYCLE: <std::__shared_ptr_emplace<PAC::PACQuery> 0xa43118080> [128] 2 (80 bytes) ROOT CYCLE: 0xa42ca9000 [32] 1 (48 bytes) ROOT CYCLE: <__NSMallocBlock__ 0xa42804de0> [48] CFNetwork invocation function for block in PAC::PACClient::initialize(void const*, __CFURL cons..." 1 (32 bytes) ROOT CYCLE: <std::__shared_ptr_pointer<BlockHolderVar<__CFString const*, __CFData const*, std::shared_ptr<__CFArray const>, std::shared_ptr<__CFError>>*, SmartBlockWithArgs<__CFString const*, __CFData const*, std::shared_ptr<__CFArray const>, std::shared_ptr<__CFError>>::Deleter> 0xa4343da80> [32] 2 (160 bytes) <NSURL 0xa42840310> [112] 1 (48 bytes) _clients --> <CFString 0xa42c08fc0> [48] 1 (160 bytes) <NWConcrete_nw_pac_resolver 0xa4280cb40> [160] 1 (48 bytes) <CFError 0xa42804ed0> [48] 1 (32 bytes) <std::__shared_ptr_pointer<__CFError*, Deleter_CFRelease> 0xa4343dc20> [32] ... 11 (1.03K) ROOT CYCLE: <CFRunLoopSource 0xa43128540> [192] 10 (864 bytes) ROOT CYCLE: <std::__shared_ptr_emplace<PAC::PACClient> 0xa430f4a80> [224] CYCLE BACK TO <CFRunLoopSource 0xa43128540> [192] 6 (400 bytes) ROOT CYCLE: <std::__shared_ptr_emplace<PAC::PACQuery> 0xa43118880> [128] 2 (80 bytes) ROOT CYCLE: 0xa428105e0 [32] 1 (48 bytes) ROOT CYCLE: <__NSMallocBlock__ 0xa428887b0> [48] CFNetwork invocation function for block in PAC::PACClient::initialize(void const*, __CFURL cons..." 1 (32 bytes) ROOT CYCLE: <std::__shared_ptr_pointer<BlockHolderVar<__CFString const*, __CFData const*, std::shared_ptr<__CFArray const>, std::shared_ptr<__CFError>>*, SmartBlockWithArgs<__CFString const*, __CFData const*, std::shared_ptr<__CFArray const>, std::shared_ptr<__CFError>>::Deleter> 0xa4343f5c0> [32] 2 (160 bytes) <NSURL 0xa428424c0> [112] 1 (48 bytes) _clients --> <CFString 0xa42c0a640> [48] 1 (160 bytes) <NWConcrete_nw_pac_resolver 0xa4280d7c0> [160] 1 (48 bytes) <CFError 0xa42888390> [48] 1 (32 bytes) <std::__shared_ptr_pointer<__CFError*, Deleter_CFRelease> 0xa4343f4c0> [32] ... The extension creates an nw_connection_t to the remote host for each handled flow like this: nw_parameters_t parameters = nw_parameters_create_secure_tcp(NW_PARAMETERS_DISABLE_PROTOCOL, NW_PARAMETERS_DEFAULT_CONFIGURATION); nw_endpoint_t connectTo = nw_endpoint_create_host([endpoint.hostname UTF8String], [endpoint.port UTF8String]); nw_connection_t connection = nw_connection_create(connectTo, parameters); When "Auto proxy discovery" is disabled, everything works as expected, and no memory leaks or issues are observed. Could you please advise on how to resolve or work around this issue? Thank you in advance!

I am working on a Network Extension (Transparent Proxy) which is used by a DLP to prevent data leaks over the network. For each incoming NEAppProxyTCPFlow, the extension instantiates a custom wrapper object that creates an outbound nw_connection_t to the target host and port using Network framework. When a client application connects to unreachable or blocked ports (e.g., 5222), our extension proxies this connection. As the destination is unreachable, the newly created connection transitions into nw_connection_state_waiting in Network Extension. Since macOS keeps nw_connection_t in the nw_connection_state_waiting state indefinitely, such connections cause system resource leaks. Over time, this leads to: exhaustion of system file descriptors and sockets. system-wide network unavailability until the extension process is killed. Could you provide best-practice recommendations for handling nw_connection_state_waiting in a Network Extension to prevent such resource leaks?

Hello, I am currently developing a printed data security feature for a cross-platform DLP system. On other platforms, this functionality relies on a cross-platform third-party library. On macOS, this library depends on the Core Graphics and AppKit frameworks. So, such dependency makes it impossible to use the code within a launch daemon, which is where this mechanism needs to run. As an alternative approach, I am considering implementing the necessary functionality inside a CUPS filter. However, I have some doubts regarding the execution context of the CUPS filter process. Is it safe to use AppKit within a CUPS filter? Thank you in advance.

Hello, I am working on a DLP (Data Leak Prevention) agent which must programmatically install our custom Root CA certificate into the System Keychain with the "Always Trust" policy. This is required for our network inspection module. The installation process is currently handled by a LaunchDaemon. I am using the following command: security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain The certificate is successfully added to the System Keychain, but the "Always Trust" policy is completely ignored. The certificate remains untrusted until the user manually opens System Settings and explicitly changes the trust settings. Our DLP agent is specifically designed for environment where MDM is not present and we can not rely on MDM to push profiles. Is it officially possible to set "Always Trust" for certificate programmatically from a LaunchDaemon? Thank you in advance!

Hello, I am working on a DLP system for macOS. The application must analyze and potentially block network traffic. Currently, I am using NETransparentProxyProvider for traffic analysis and looking for the best solution to block network traffic. I believe the blocking can be implemented by capturing the flow and choosing not to proxy/forward it further (dropping it). However, I am unsure how the OS and other applications will react to this approach. As far as I know, macOS provides a dedicated NEFilterDataProvider (Content Filter) specifically designed for traffic filtering and blocking. I have two questions regarding the architecture: Is it safe to block flows directly using a Transparent Proxy? Will dropping/ignoring the flow without forwarding it cause any unexpected system behavior, socket hangups, or performance issues? Or is it highly recommended to strictly use a Content Filter (NEFilterDataProvider) for the blocking aspect? Can a single container app install and manage more than one Network Extension in the system? For example, if the best practice dictates separating the logic, can my single DLP macOS application bundle and install both a Transparent Proxy (for analysis/routing) and a Content Filter (for blocking) simultaneously? Thank you in advance!

Hello, I am working on a network security and DLP (Data Loss Prevention) solution. A core requirement of our architecture is the ability to modify network traffic payloads in-flight (e.g., stripping sensitive data or altering packets). So, the only way to implement this is via the NETransparentProxyProvider which allows us to handle, evaluate, and modify network flows (NEAppProxyFlow). However, because this is such a powerful mechanism, my primary goal is to ensure the absolute stability of the operating system. I want to minimize the risk of interfering with core Apple services. When evaluating a flow, I have access to NEFlowMetaData, specifically properties like sourceAppUniqueIdentifier and sourceAppAuditToken. Could you please assist me with the following questions: Is there a recommended list of Apple system Application IDs (Bundle IDs) or executable names that should be strictly bypassed (ignored) by the Network Extension to maintain system integrity? Since system daemons can change between OS releases, are there any programmatic best practices or specific rules to dynamically identify core OS traffic that must not be intercepted? Are there any specific network ports or protocols that Apple strongly recommends excluding from NENetworkRule matches at the proxy provider configuration level to ensure daemons like apsd or mDNSResponder function correctly? Thank you in advance.

Hello, I am working on a DLP solution for macOS that relies on the Network Extension (NETransparentProxyProvider) for network traffic analysis. Could you please clarify: is it technically possible and officially supported to use a LaunchAgent as the container app to install and manage the Network Extension? If not, what is the recommended approach in case of GUI less application? Thank you in advance.

Hello, I am developing a macOS Launch Daemon (packaged as a bundle) that acts as an XPC server. For debugging purposes, I am trying to run the daemon's executable directly from the terminal via sudo ./mydaemon.app/Contents/MacOS/myexecutable. Initially, I added the com.apple.security.application-groups entitlement to the daemon. However, when starting the process, it failed to create the XPC service with the following errors: Unsatisfied entitlements: com.apple.security.application-groups Soft-restriction provisioning profile validation failure: Error Domain=AppleMobileFileIntegrityError Code=-413 "No matching profile found" UserInfo={NSURL=, unsatisfiedEntitlements=, NSLocalizedDescription=No matching profile found} listener failed to activate: xpc_error=[1: Operation not permitted] To resolve the profile validation failure, I registered a new App Group in the Apple Developer Portal, generated a new provisioning profile for the daemon that includes this group, and embedded it into the bundle (Contents/embedded.provisionprofile). Now, the previous profile error is gone, but I am getting a new identity conflict error, and the XPC listener still fails: Two equal instances have unequal identities. <anon<myproc_name>(501) pid=2818 AUID=501> and <anon<myproc_name>(501)(262) pid=2818 AUID=262> listener failed to activate: xpc_error=[1: Operation not permitted] My questions are: What exactly causes the Two equal instances have unequal identities error? I noticed the Audit UID difference (AUID=501 vs AUID=262). Why does NSXPCListener still fail with Operation not permitted? What is the recommended workflow for debugging a Launch Daemon that requires an App Group provisioning profile for XPC communication? Thank you in advance!

Hello, How does macOS handle coexistence between multiple Transparent Proxy providers from different vendors if their network rules overlap and one provider modifies the traffic? Thank you in advance!

Hello, Is it possible for a Network Extension (running in its sandbox) to act as a client for an XPC service hosted by a Launch Daemon (e.g., to offload data processing)? Are there any specific sandbox restrictions or entitlement requirements for this type of XPC communication? Thank you in advance!