Uncontrolled recursion in the json2pb component in Apache bRPC (version < 1.15.0) on all platforms allows remote attackers to make the server crash via sending deep recursive json data.
Root Cause: The bRPC json2pb component uses rapidjson to parse json data from the network. The rapidjson parser uses a recursive parsing method by default. If the input json has a large depth of recursive structure, the parser function may run into stack overflow.
Affected Scenarios: Use bRPC server with protobuf message to serve http+json requests from untrusted network. Or directly use JsonToProtoMessage to convert json from untrusted input.
How to Fix: (Choose one of the following options) 1. Upgrade bRPC to version 1.15.0, which fixes this issue. 2. Apply this patch: https://github.com/apache/brpc/pull/3099
Note: No matter which option
you choose, you should know that the fix introduces a recursion depth limit with default value 100. It affects these functions:
ProtoMessageToJson, ProtoMessageToProtoJson, JsonToProtoMessage, and ProtoJsonToProtoMessage.
If your requests contain json or protobuf messages that have a depth exceeding the limit, the request will be failed after applying the fix. You can modify the gflag json2pb_max_recursion_depth to change the limit.
CVSS Details
- CVSS 3.1 Base Score: 7.5
- CVSS 3.1 Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
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