Hyperledger Indy Node is the server portion of a distributed ledger purpose-built for decentralized identity. In Hyperledger Indy before version 1.12.4, there is lack of signature verification on a specific transaction which enables an attacker to make certain unauthorized alterations to the ledger. Updating a DID with a nym transaction will be written to the ledger if neither ROLE or VERKEY are being changed, regardless of sender. A malicious DID with no particular role can ask an update for another DID (but cannot modify its verkey or role). This is bad because 1) Any DID can write a nym transaction to the ledger (i.e., any DID can spam the ledger with nym transactions), 2) Any DID can change any other DID's alias, 3) The update transaction modifies the ledger metadata associated with a DID.

Affected: PyPI: indy-node

# Name Updating a DID with a nym transaction will be written to the ledger if neither ROLE or VERKEY are being changed, regardless of sender.

# Description A malicious DID with no particular role can ask an update for another DID (but cannot modify its verkey or role). This is bad because: 1. Any DID can write a nym transaction to the ledger (i.e., any DID can spam the ledger with nym transactions). 1. Any DID can change any other DID's alias. 1. The update transaction modifies the ledger metadata associated with a DID.

# Expected vs Observed We expect that if a DID (with no role) wants to update another DID (not its own or one it is the endorser), then the nodes should refuse the request. We can see that requirements in the [Indy default auth_rules](https://github.com/hyperledger/indy-node/blob/master/docs/source/auth_rules.md) in Section "Who is the owner" in the last point of "Endorser using".

We observe that with a normal DID, we can update the field `from` for a random DID, for example, the one of a TRUSTEE. It creates then a new transaction on the ledger.

# Explanation of the attack We first begin to connect to the pool and open a wallet. Then, we will use a TRUSTEE (but can also be a STEWARD or an ENDORSER) DID `V4SGRU86Z58d6TV7PBUe6f`. We ask the information about `V4SGRU86Z58d6TV7PBUe6f` with a get-nym. We create a new DID `V4SGRU86Z58d6TV7PBUe1a` signed by `V4SGRU86Z58d6TV7PBUe6f` with no role. For the rest of the attack, we will use `V4SGRU86Z58d6TV7PBUe1a`…

Affected: PyPI: indy-node

Hyperledger Indy Node is the server portion of a distributed ledger purpose-built for decentralized identity. In Hyperledger Indy before version 1.12.4, there is lack of signature verification on a specific transaction which enables an attacker to make certain unauthorized alterations to the ledger. Updating a DID with a nym transaction will be written to the ledger if neither ROLE or VERKEY are being changed, regardless of sender. A malicious DID with no particular role can ask an update for another DID (but cannot modify its verkey or role). This is bad because 1) Any DID can write a nym transaction to the ledger (i.e., any DID can spam the ledger with nym transactions), 2) Any DID can change any other DID's alias, 3) The update transaction modifies the ledger metadata associated with a DID.