A Missing Release of Memory after Effective Lifetime vulnerability in the Periodic Packet Management Daemon (ppmd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker to cause a
Denial-of-Service (DoS).
When a BFD session configured with authentication flaps, ppmd memory can leak. Whether the leak happens depends on a race condition which is outside the attackers control. This issue only affects BFD operating in distributed aka delegated (which is the default behavior) or inline mode.
Whether the leak occurs can be monitored with the following CLI command:
show ppm request-queue
FPC Pending-request
fpc0 2
request-total-pending: 2
where a continuously increasing number of pending requests is indicative of the leak.
This issue affects:
Junos OS:
- All versions before 21.2R3-S8,
- 21.4 versions before 21.4R3-S7,
- 22.1 versions before 22.1R3-S4,
- 22.2 versions before 22.2R3-S4,
- 22.3 versions before 22.3R3,
- 22.4 versions before 22.4R2-S2, 22.4R3.
Junos OS Evolved:
- All versions before 21.2R3-S8-EVO,
- 21.4-EVO versions before 21.4R3-S7-EVO,
- 22.2-EVO versions before 22.2R3-S4-EVO,
- 22.3-EVO versions before 22.3R3-EVO,
- 22.4-EVO versions before 22.4R3-EVO.
Weakness
The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.
Potential Mitigations
- Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
- For example, glibc in Linux provides protection against free of invalid pointers.
- When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
- To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.
References