Source: cna@vuldb.com
A vulnerability was detected in wasm3 up to 0.5.0. Impacted is the function op_SetSlot_i32/op_CallIndirect of the file m3_exec.h. Performing manipulation results in memory corruption. The attack needs to be approached locally. The exploit is now public and may be used. Unfortunately, the project has no active maintainer at the moment.
wasm3, a WebAssembly interpreter, is vulnerable to a memory corruption flaw due to improper handling of memory operations within the op_SetSlot_i32 and op_CallIndirect functions. This allows for local exploitation, potentially leading to arbitrary code execution and system compromise, as the project lacks an active maintainer, leaving the vulnerability unpatched and the system at risk.
Step 1: Crafted WebAssembly Module: The attacker crafts a malicious WebAssembly module designed to trigger the vulnerability. This module will contain instructions that call op_SetSlot_i32 or op_CallIndirect in a way that exploits the memory corruption flaw.
Step 2: Module Loading: The malicious WebAssembly module is loaded into the wasm3 interpreter.
Step 3: Triggering the Vulnerability: The attacker executes the WebAssembly module, which calls the vulnerable functions with carefully crafted arguments. These arguments are designed to cause an out-of-bounds write or a call to an arbitrary memory address.
Step 4: Memory Corruption: The vulnerable functions, due to the lack of proper bounds checking or offset calculations, write data to an unintended memory location, corrupting the program's memory.
Step 5: Code Execution (Potential): If the attacker successfully overwrites the instruction pointer or other critical data, they can redirect the program's execution flow to arbitrary code, achieving code execution.
The vulnerability stems from a flaw in how wasm3 handles memory access during the execution of WebAssembly instructions. Specifically, the op_SetSlot_i32 and op_CallIndirect functions within m3_exec.h are susceptible to memory corruption. The root cause is likely an insufficient bounds check or improper calculation of memory offsets when writing to or calling memory locations. This can lead to a buffer overflow or other memory-related errors, allowing an attacker to overwrite critical data structures, including the instruction pointer, and gain control of the program's execution flow. The lack of active maintenance exacerbates the issue, as no patches are forthcoming.
While no specific APTs are directly named, the public availability of the exploit and the ease of exploitation make this a high-risk vulnerability. The lack of a patch makes it attractive to a wide range of attackers. CISA KEV status: Not Listed (as of this analysis, but the lack of a patch and public exploit makes it a candidate for future inclusion).
Monitor for unusual memory access patterns within the wasm3 interpreter process.
Analyze WebAssembly modules for suspicious instructions, particularly those involving op_SetSlot_i32 and op_CallIndirect calls with potentially malicious arguments.
Implement runtime monitoring to detect memory corruption events, such as segmentation faults or unexpected program behavior.
Review system logs for errors related to wasm3 operations, especially those occurring during module loading or execution.
Network traffic analysis for the transfer of WebAssembly modules, especially from untrusted sources.
If possible, migrate to a maintained WebAssembly runtime. This is the most effective long-term solution.
If migration is not feasible, isolate the wasm3 interpreter within a sandboxed environment to limit the impact of a successful exploit.
Implement input validation and sanitization for all data passed to the wasm3 interpreter, especially arguments to functions like op_SetSlot_i32 and op_CallIndirect.
Disable or restrict the use of WebAssembly modules from untrusted sources.
Monitor for and promptly investigate any suspicious activity related to wasm3.