Capstone is a disassembly framework. In versions 6.0.0-Alpha5 and prior, Skipdata length is not bounds-checked, so a user-provided skipdata callback can make cs_disasm/cs_disasm_iter memcpy more than 24 bytes into cs_insn.bytes, causing a heap buffer overflow in the disassembly path. Commit cbef767ab33b82166d263895f24084b75b316df3 fixes the issue.
Weakness
A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Capstone | Capstone-engine | * | 6.0.0 (excluding) |
| Capstone | Capstone-engine | 6.0.0-alpha1 (including) | 6.0.0-alpha1 (including) |
| Capstone | Capstone-engine | 6.0.0-alpha2 (including) | 6.0.0-alpha2 (including) |
| Capstone | Capstone-engine | 6.0.0-alpha3 (including) | 6.0.0-alpha3 (including) |
| Capstone | Capstone-engine | 6.0.0-alpha4 (including) | 6.0.0-alpha4 (including) |
| Capstone | Capstone-engine | 6.0.0-alpha5 (including) | 6.0.0-alpha5 (including) |
| Red Hat Enterprise Linux 10 | RedHat | capstone-0:5.0.1-7.el10_1 | * |
| Red Hat Enterprise Linux 10.0 Extended Update Support | RedHat | capstone-0:5.0.1-7.el10_0 | * |
| Red Hat Enterprise Linux 9 | RedHat | capstone-0:4.0.2-11.el9_7 | * |
| Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions | RedHat | capstone-0:4.0.2-5.el9_0 | * |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | RedHat | capstone-0:4.0.2-11.el9_2 | * |
| Red Hat Enterprise Linux 9.4 Extended Update Support | RedHat | capstone-0:4.0.2-11.el9_4 | * |
| Red Hat Enterprise Linux 9.6 Extended Update Support | RedHat | capstone-0:4.0.2-11.el9_6 | * |
| Red Hat Hardened Images | RedHat | capstone-main-5.0.7-0.1.hum1 | * |
| Capstone | Ubuntu | esm-apps/xenial | * |
| Capstone | Ubuntu | plucky | * |
| Capstone | Ubuntu | questing | * |
Potential Mitigations
- Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking.
- D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
- Run or compile the software using features or extensions that randomly arrange the positions of a program’s executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code.
- Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as “rebasing” (for Windows) and “prelinking” (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking.
- For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].