macOS XNU - Missing Locking in checkdirs_callback() Enables Race with fchdir_common()

On macOS, when a new mount point is created, the kernel uses checkdirs to, as a comment above the function explains: "Scan all active processes to see if any of them have a current or root directory onto which the new filesystem has just been mounted. If so, replace them with the new mount point....

XNU - Remote Double-Free via Data Race in IPComp Input Path

=== Summary === This report describes a bug in the XNU implementation of the IPComp protocol https://tools.ietf.org/html/rfc3173. This bug can be remotely triggered by an attacker who is able to send traffic to a macOS system iOS AFAIK isn't affected over two network interfaces at the same time...

XNU - Remote Double-Free via Data Race in IPComp Input Path Exploit

=== Summary === This report describes a bug in the XNU implementation of the IPComp protocol https://tools.ietf.org/html/rfc3173. This bug can be remotely triggered by an attacker who is able to send traffic to a macOS system iOS AFAIK isn't affected over two network interfaces at the same time...

XNU - Remote Double-Free via Data Race in IPComp Input Path

XNU - Remote Double-Free via Data Race in IPComp Input Path === Summary === This report describes a bug in the XNU implementation of the IPComp protocol https://tools.ietf.org/html/rfc3173. This bug can be remotely triggered by an attacker who is able to send traffic to a macOS system iOS AFAIK...

The vulnerability in the XNU kernel of iOS, Mac OS, and TV OS allows attackers to perform unauthorized changes to the memory shared among processes.

The vulnerability of the XNU-based operating systems such as iOS, Mac OS, and TV OS is related to errors in the memory initialization mechanism. Exploiting this vulnerability allows an attacker to perform unauthorized changes to the memory shared among processes, using specially crafted executabl...

Apple macOS 10.14.5 iOS 12.3 XNU - in6_pcbdetach Stale Pointer Use-After-Free

Apple macOS 10.14.5 iOS 12.3 XNU - in6pcbdetach Stale Pointer Use-After-Free Reproduction Repros on 10.14.3 when run as root. It may need multiple tries to trigger. $ clang -o in6selectsrc in6selectsrc.cc $ while 1; do sudo ./in6selectsrc; done res0: 3 res1: 0 res1.5: -1 // failure expected here...

XNU Stale Pointer Use-After-Free

XNU: Use-after-free due to stale pointer left by in6pcbdetach Related CVE Numbers: CVE-2019-8605Fixed-2019-May-13. Reproduction Repros on 10.14.3 when run as root. It may need multiple tries to trigger. $ clang -o in6selectsrc in6selectsrc.cc $ while 1; do sudo ./in6selectsrc; done res0: 3 res1: ...

Apple macOS < 10.14.5 / iOS < 12.3 XNU - 'in6_pcbdetach' Stale Pointer Use-After-Free

Reproduction Repros on 10.14.3 when run as root. It may need multiple tries to trigger. $ clang -o in6selectsrc in6selectsrc.cc $ while 1; do sudo ./in6selectsrc; done res0: 3 res1: 0 res1.5: -1 // failure expected here res2: 0 done ... crash Explanation The following snippet is taken from...

macOS < 10.14.5 / iOS < 12.3 XNU - Wild-read due to bad cast in stf_ioctl Exploit

macOS ifaaddr-safamily != AFINET6 // - crash here IFAUNLOCKifa; error = EAFNOSUPPORT; break; Note that IFALOCK is called on user-provided data; it appears that there is an opportunity for memory corruption a controlled write when using indirect mutexes via LCKMTXTAGINDIRECT see lckmtxlockslow...

Apple macOS < 10.14.5 / iOS < 12.3 XNU - Wild-read due to bad cast in stf_ioctl

/ Reproduction Tested on macOS 10.14.3: $ clang -o stfwildread stfwildread.cc $ ./stfwildread Explanation SIOCSIFADDR is an ioctl that sets the address of an interface. The stf interface ioctls are handled by the stfioctl function. The crash occurs in the following case where a struct ifreq is re...

Apple macOS 10.14.5 iOS 12.3 XNU - Wild-read due to bad cast in stf_ioctl

Apple macOS 10.14.5 iOS 12.3 XNU - Wild-read due to bad cast in stfioctl / Reproduction Tested on macOS 10.14.3: $ clang -o stfwildread stfwildread.cc $ ./stfwildread Explanation SIOCSIFADDR is an ioctl that sets the address of an interface. The stf interface ioctls are handled by the stfioctl...

iOS 12.2 macOS 10.14.4 XNU - pidversion Increment During execve is Unsafe

iOS 12.2 macOS 10.14.4 XNU - pidversion Increment During execve is Unsafe Privileged IPC services in userspace often have to verify the security context of their client processes such as whether the client is sandboxed, has a specific entitlement, or is signed by some code signing authority. This...

iOS < 12.2 / macOS < 10.14.4 XNU - pidversion Increment During execve is Unsafe Exploit

iOS 12.2 / macOS 10.14.4 XNU - pidversion Increment During execve is Unsafe Exploit Privileged IPC services in userspace often have to verify the security context of their client processes such as whether the client is sandboxed, has a specific entitlement, or is signed by some code signing...

Splitting atoms in XNU

Posted by Ian Beer, Google Project Zero TL;DR A locking bug in the XNU virtual memory subsystem allowed violation of the preconditions required for the correctness of an optimized virtual memory operation. This was abused to create shared memory where it wasn't expected, allowing the creation of ...

Project Zero Discloses High-Severity Apple macOS Flaw

Researchers have disclosed what they say is a high-severity security flaw in Apple’s MacOS operating system – which has not yet been patched. The flaw gives an attacker privileges to perform malicious actions on a mounted filesystem – without the victim knowing. The Google Project Zero team...

macOS XNU - Copy-on-Write Behavior #Bypass via Mount of User-Owned Filesystem Image Exploit

XNU has various interfaces that permit creating copy-on-write copies of data between processes, including out-of-line message descriptors in mach messages. It is important that the copied memory is protected against later modifications by the source process; otherwise, the source process might be...

macOS XNU - Copy-on-Write Behavior Bypass via Mount of User-Owned Filesystem Image

macOS XNU - Copy-on-Write Behavior Bypass via Mount of User-Owned Filesystem Image XNU has various interfaces that permit creating copy-on-write copies of data between processes, including out-of-line message descriptors in mach messages. It is important that the copied memory is protected agains...

macOS XNU - Copy-on-Write Behavior Bypass via Mount of User-Owned Filesystem Image

XNU has various interfaces that permit creating copy-on-write copies of data between processes, including out-of-line message descriptors in mach messages. It is important that the copied memory is protected against later modifications by the source process; otherwise, the source process might be...

macOS XNU - Copy-on-Write Behaviour Bypass via Partial-Page Truncation of File Exploit

/ XNU has various interfaces that permit creating copy-on-write copies of data between processes, including out-of-line message descriptors in mach messages. It is important that the copied memory is protected against later modifications by the source process; otherwise, the source process might ...

macOS < 10.14.3 / iOS < 12.1.3 XNU - vm_map_copy Optimization which Requires Atomicity isn&#0

/ vmmapcopyininternal in vmmap.c converts a region of a vmmap into "copied in" form, constructing a vmmapcopy structure representing the copied memory which can then be mapped into another vmmap or the same one. The function contains a while loop which walks through each of the vmmapentry...