An Out-of-bounds Read vulnerability in Juniper Networks Junos OS and Junos OS Evolveds routing protocol daemon (rpd) allows an unauthenticated, network-based attacker to send malformed BGP packets to a device configured with packet receive trace options enabled to crash rpd.
This issue affects:
Junos OS:
- from 21.2R3-S8 before 21.2R3-S9,
- from 21.4R3-S7 before 21.4R3-S9,
- from 22.2R3-S4 before 22.2R3-S5,
- from 22.3R3-S2 before 22.3R3-S4,
- from 22.4R3 before 22.4R3-S5,
- from 23.2R2 before 23.2R2-S2,
- from 23.4R1 before 23.4R2-S1,
- from 24.2R1 before 24.2R1-S1, 24.2R2.
Junos OS Evolved:
- from 21.4R3-S7-EVO before 21.4R3-S9-EVO,
- from 22.2R3-S4-EVO before 22.2R3-S5-EVO,
- from 22.3R3-S2-EVO before 22.3R3-S4-EVO,
- from 22.4R3-EVO before 22.4R3-S5-EVO,
- from 23.2R2-EVO before 23.2R2-S2-EVO,
- from 23.4R1-EVO before 23.4R2-S1-EVO,
- from 24.2R1-EVO before 24.2R1-S2-EVO, 24.2R2-EVO.
This issue requires a BGP session to be established.
This issue can propagate and multiply through multiple ASes until reaching vulnerable devices.
This issue affects iBGP and eBGP.
This issue affects IPv4 and IPv6.
An indicator of compromise may be the presence of malformed update messages in a neighboring AS which is unaffected by this issue:
For example, by issuing the command on the neighboring device:
show log messages
Reviewing for similar messages from devices within proximity to each other may indicate this malformed packet is propagating:
rpd[]: Received malformed update from (External AS <AS#>)
and
rpd[]: Malformed Attribute
Weakness
The product reads data past the end, or before the beginning, of the intended buffer.
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.
- To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.
References