The png_decompress_chunk function in pngrutil.c in libpng 1.0.x before 1.0.53, 1.2.x before 1.2.43, and 1.4.x before 1.4.1 does not properly handle compressed ancillary-chunk data that has a disproportionately large uncompressed representation, which allows remote attackers to cause a denial of service (memory and CPU consumption, and application hang) via a crafted PNG file, as demonstrated by use of the deflate compression method on data composed of many occurrences of the same character, related to a decompression bomb attack.
The product does not properly control the allocation and maintenance of a limited resource.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libpng | Libpng | 1.0.0 (including) | 1.0.53 (excluding) |
| Libpng | Libpng | 1.2.0 (including) | 1.2.43 (excluding) |
| Libpng | Libpng | 1.4.0 (including) | 1.4.1 (excluding) |
| Red Hat Enterprise Linux 3 | RedHat | libpng-2:1.2.2-30 | * |
| Red Hat Enterprise Linux 3 | RedHat | libpng10-0:1.0.13-21 | * |
| Red Hat Enterprise Linux 4 | RedHat | libpng-2:1.2.7-3.el4_8.3 | * |
| Red Hat Enterprise Linux 4 | RedHat | libpng10-0:1.0.16-3.el4_8.4 | * |
| Red Hat Enterprise Linux 5 | RedHat | libpng-2:1.2.10-7.1.el5_5.3 | * |
| Firefox | Ubuntu | dapper | * |
| Firefox | Ubuntu | hardy | * |
| Libpng | Ubuntu | dapper | * |
| Libpng | Ubuntu | devel | * |
| Libpng | Ubuntu | hardy | * |
| Libpng | Ubuntu | intrepid | * |
| Libpng | Ubuntu | jaunty | * |
| Libpng | Ubuntu | karmic | * |
| Libpng | Ubuntu | upstream | * |
Mitigation of resource exhaustion attacks requires that the target system either:
The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question.
The second solution is simply difficult to effectively institute – and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.