A Heap-based Buffer Overflow vulnerability in the telemetry sensor process (sensord) of Juniper Networks Junos OS on MX240, MX480, MX960 platforms using MPC10E causes a steady increase in memory utilization, ultimately leading to a Denial of Service (DoS).
When the device is subscribed to a specific subscription on Junos Telemetry Interface, a slow memory leak occurs and eventually all resources are consumed and the device becomes unresponsive. A manual reboot of the Line Card will be required to restore the device to its normal functioning.
This issue is only seen when telemetry subscription is active.
The Heap memory utilization can be monitored using the following command:
> show system processes extensive
The following command can be used to monitor the memory utilization of the specific sensor
> show system info | match sensord
PID NAME MEMORY PEAK MEMORY %CPU THREAD-COUNT CORE-AFFINITY UPTIME
1986 sensord 877.57MB 877.57MB 2 4 0,2-15 7-21:41:32
This issue affects Junos OS:
- from 21.2R3-S5 before 21.2R3-S7,
- from 21.4R3-S4 before 21.4R3-S6,
- from 22.2R3 before 22.2R3-S4,
- from 22.3R2 before 22.3R3-S2,
- from 22.4R1 before 22.4R3,
- from 23.2R1 before 23.2R2.
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().
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