OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. In versions before 3.2.11, 3.3.0 through 3.3.12, and 3.4.0 through 3.4.13, exrmultiview can write past a heap allocation when it combines two attacker-supplied, individually valid scanline EXR files whose union dataWindow is not aligned to one views channel subsampling. The utility allocates sampled channel storage using a truncated union_width / xSampling, then reads the sampled input through a Slice based on the misaligned union window, producing a heap out-of-bounds write. The trigger is normal public-tool processing, such as exrmultiview left A.exr right B.exr out.exr with crafted but valid inputs, so this is not solely an API or caller-precondition issue. This issue is fixed in versions 3.2.11, 3.3.13, and 3.4.14.
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 |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | RedHat | openexr-0:3.1.10-8.el10_2.4 | * |
| Red Hat Enterprise Linux 9 | RedHat | openexr-0:3.1.1-3.el9_8.4 | * |
| Openexr | Ubuntu | upstream | * |
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].
Related Attack Patterns
References
- https://github.com/AcademySoftwareFoundation/openexr/commit/77ee19c021398b1c56f32c3af8347e365dbd4f33
- https://github.com/AcademySoftwareFoundation/openexr/commit/c644ac2dfeac82939c81a8551d6f4b7859f63add
- https://github.com/AcademySoftwareFoundation/openexr/commit/e2300a3d54a93d20a36a86b82f3a506c4c91476f
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-gjf7-wjjw-xq56
- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-gjf7-wjjw-xq56