CVE-2022-22223

On QFX10000 Series devices using Juniper Networks Junos OS when configured as transit IP/MPLS penultimate hop popping (PHP) nodes with link aggregation group (LAG) interfaces, an Improper Validation of Specified Index, Position, or Offset in Input weakness allows an attacker sending certain IP packets to cause multiple interfaces in the LAG to detach causing a Denial of Service (DoS) condition. Continued receipt and processing of these packets will sustain the Denial of Service. This issue affects IPv4 and IPv6 packets. Packets of either type can cause and sustain the DoS event. These packets can be destined to the device or be transit packets. On devices such as the QFX10008 with line cards, line cards can be restarted to restore service. On devices such as the QFX10002 you can restart the PFE service, or reboot device to restore service. This issue affects: Juniper Networks Junos OS on QFX10000 Series: All versions prior to 15.1R7-S11; 18.4 versions prior to 18.4R2-S10, 18.4R3-S10; 19.1 versions prior to 19.1R3-S8; 19.2 versions prior to 19.2R3-S4; 19.3 versions prior to 19.3R3-S5; 19.4 versions prior to 19.4R2-S6, 19.4R3-S7; 20.1 versions prior to 20.1R3-S3; 20.2 versions prior to 20.2R3-S3; 20.3 versions prior to 20.3R3-S2; 20.4 versions prior to 20.4R3-S4; 21.1 versions prior to 21.1R3; 21.2 versions prior to 21.2R3-S3; 21.3 versions prior to 21.3R3-S1. An indicator of compromise may be seen by issuing the command: request pfe execute target fpc0 command show jspec pechip[3] registers ps l2_node 10 timeout 0 | refresh 1 | no-more and reviewing for backpressured output; for example: GOT: 0x220702a8 pe.ps.l2_node[10].pkt_cnt 00000076 GOT: 0x220702b4 pe.ps.l2_node[10].backpressured 00000002 «« STICKS HERE and requesting detail on the pepic wanio: request pfe execute target fpc0 command show pepic 0 wanio-info timeout 0 | no-more | match xe-0/0/0:2 GOT: 3 xe-0/0/0:2 10 6 3 0 1 10 189 10 0x6321b088 «< LOOK HERE as well as looking for tail drops looking at the interface queue, for example: show interfaces queue xe-0/0/0:2 resulting in: Transmitted: Total-dropped packets: 1094137 0 pps « LOOK HERE

Weakness

The product receives input that is expected to specify an index, position, or offset into an indexable resource such as a buffer or file, but it does not validate or incorrectly validates that the specified index/position/offset has the required properties.

Affected Software

Extended Description

Often, indexable resources such as memory buffers or files can be accessed using a specific position, index, or offset, such as an index for an array or a position for a file. When untrusted input is not properly validated before it is used as an index, attackers could access (or attempt to access) unauthorized portions of these resources. This could be used to cause buffer overflows, excessive resource allocation, or trigger unexpected failures.

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.

References

• https://kb.juniper.net/JSA69873
• https://kb.juniper.net/JSA69873