An Improper Input Validation vulnerability in the syslog stream TCP transport of Juniper Networks Junos OS on MX240, MX480 and MX960 devices with MX-SPC3 Security Services Card allows an unauthenticated, network-based attacker, to send specific spoofed packets to cause a CPU Denial of Service (DoS) to the MX-SPC3 SPUs.

Continued receipt and processing of these specific packets will sustain the DoS condition.

This issue affects Junos OS:  *  All versions before 22.2R3-S6,
  *  from 22.4 before 22.4R3-S4,
  *  from 23.2 before 23.2R2-S3,
  *  from 23.4 before 23.4R2-S4,
  *  from 24.2 before 24.2R1-S2, 24.2R2


An indicator of compromise will indicate the SPC3 SPUs utilization has spiked.


For example: 
   user@device> show services service-sets summary
                     Service sets                                                                               CPU
  Interface          configured       Bytes used             Session bytes used        Policy bytes used        utilization
  "interface"          1              "bytes" (percent%)     "sessions" ("percent"%)   "bytes" ("percent"%)     99.97 % OVLD  <<<<<< look for high CPU usage

AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:C/RE:M/U:Amber

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE-20

https://supportportal.juniper.net/JSA96459