Oracle-BI (CVE-2020-2950)

AMF deseiralize

Version: 5.5.0.0.0, 11.1.1.9.0, 12.2.1.3.0

**Install:**https://www.sql.edu.vn/obiee/oracle-business-intelligence-12c/

Ref: https://peterjson.medium.com/cve-2020-2950-turning-amf-deserialize-bug-to-java-deserialize-bug-2984a8542b6f

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Exploit - PoC

amf.bin

Header cmd with base64 and child !!

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Debug trace bug

URL: /analytics/jbips/messagebroker/cs/

• Handle request -> processCall()

• Get inputstream -> deserialize AMF package

• Get Object AMF -> deserilize

• If matching type -> AMF readobject (AMF3DATA.class)

• AMF3DATA.class -> AMF3ObjectInput
• In AMF3ObjectInut -> readComplexObject

• In readComplexObject:
  • If class deseriliaze is externalizable -> radExternalchain
  • else setFiled

• AMF deserialize chain -> readExternal Chain