Calling the scanf family of functions with a %mc (mallocd character match) in the GNU C Library version 2.7 to version 2.43 with a format width specifier with an explicit width greater than 1024 could result in a one byte heap buffer overflow.
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 |
|---|---|---|---|
| Glibc | Gnu | 2.7 (including) | 2.43 (including) |
| Red Hat Enterprise Linux 10 | RedHat | glibc-0:2.39-126.el10_2 | * |
| Red Hat Enterprise Linux 10.0 Extended Update Support | RedHat | glibc-0:2.39-46.el10_0.5 | * |
| Red Hat Enterprise Linux 6 Extended Lifecycle Support - EXTENSION | RedHat | glibc-0:2.12-1.212.el6_10.4 | * |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | RedHat | glibc-0:2.17-326.el7_9.6 | * |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | RedHat | compat-glibc-1:2.12-4.el7_9.1 | * |
| Red Hat Enterprise Linux 8 | RedHat | glibc-0:2.28-251.el8_10.38 | * |
| Red Hat Enterprise Linux 8 | RedHat | glibc-0:2.28-251.el8_10.38 | * |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | RedHat | glibc-0:2.28-151.el8_4.6 | * |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | RedHat | glibc-0:2.28-151.el8_4.6 | * |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | RedHat | glibc-0:2.28-189.13.el8_6 | * |
| Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On | RedHat | glibc-0:2.28-189.13.el8_6 | * |
| Red Hat Enterprise Linux 8.8 Telecommunications Update Service | RedHat | glibc-0:2.28-225.el8_8.17 | * |
| Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions | RedHat | glibc-0:2.28-225.el8_8.17 | * |
| Red Hat Enterprise Linux 9 | RedHat | glibc-0:2.34-272.el9_8 | * |
| Red Hat Enterprise Linux 9 | RedHat | glibc-0:2.34-272.el9_8 | * |
| Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions | RedHat | glibc-0:2.34-60.el9_2.20 | * |
| Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions | RedHat | glibc-0:2.34-100.el9_4.13 | * |
| Red Hat Enterprise Linux 9.6 Extended Update Support | RedHat | glibc-0:2.34-168.el9_6.25 | * |
| Red Hat Hardened Images | RedHat | glibc-main-2.42-12.hum1 | * |
| Red Hat Insights proxy 1.5 | RedHat | insights-proxy/insights-proxy-container-rhel9:1782890503 | * |
| Glibc | Ubuntu | esm-infra/xenial | * |
| Glibc | 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].