A heap-based buffer overflow flaw was found in the Fribidi package and affects the fribidi_cap_rtl_to_unicode() function of the fribidi-char-sets-cap-rtl.c file. This flaw allows an attacker to pass a specially crafted file to the Fribidi application with the –caprtl option, leading to a crash and causing a denial of service.
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 |
| Fribidi |
Gnu |
* |
1.0.12 (excluding) |
| Red Hat Enterprise Linux 8 |
RedHat |
fribidi-0:1.0.4-9.el8 |
* |
| Red Hat Enterprise Linux 9 |
RedHat |
fribidi-0:1.0.10-6.el9.2 |
* |
| Fribidi |
Ubuntu |
bionic |
* |
| Fribidi |
Ubuntu |
devel |
* |
| Fribidi |
Ubuntu |
esm-infra-legacy/trusty |
* |
| Fribidi |
Ubuntu |
esm-infra/xenial |
* |
| Fribidi |
Ubuntu |
focal |
* |
| Fribidi |
Ubuntu |
impish |
* |
| Fribidi |
Ubuntu |
jammy |
* |
| Fribidi |
Ubuntu |
trusty |
* |
| Fribidi |
Ubuntu |
trusty/esm |
* |
| Fribidi |
Ubuntu |
upstream |
* |
| Fribidi |
Ubuntu |
xenial |
* |
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].
References