389-ds-base before versions 1.4.0.9, 1.3.8.1, 1.3.6.15 did not properly handle long search filters with characters needing escapes, possibly leading to buffer overflows. A remote, unauthenticated attacker could potentially use this flaw to make ns-slapd crash via a specially crafted LDAP request, thus resulting in 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 |
| 389_directory_server |
Fedoraproject |
1.3.6.0 (including) |
1.3.6.15 (excluding) |
| 389_directory_server |
Fedoraproject |
1.4.0.0 (including) |
1.4.0.9 (excluding) |
| 389_directory_server |
Fedoraproject |
1.3.8.1 (including) |
1.3.8.1 (including) |
| 389_directory_server |
Fedoraproject |
1.3.8.2 (including) |
1.3.8.2 (including) |
| Red Hat Enterprise Linux 6 |
RedHat |
389-ds-base-0:1.2.11.15-95.el6_9 |
* |
| Red Hat Enterprise Linux 7 |
RedHat |
389-ds-base-0:1.3.7.5-21.el7_5 |
* |
| 389-ds-base |
Ubuntu |
artful |
* |
| 389-ds-base |
Ubuntu |
bionic |
* |
| 389-ds-base |
Ubuntu |
cosmic |
* |
| 389-ds-base |
Ubuntu |
esm-apps/bionic |
* |
| 389-ds-base |
Ubuntu |
esm-apps/xenial |
* |
| 389-ds-base |
Ubuntu |
trusty |
* |
| 389-ds-base |
Ubuntu |
upstream |
* |
| 389-ds-base |
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