Vulnerabilities > CVE-2020-26241 - Incorrect Calculation vulnerability in Ethereum GO Ethereum

047910
CVSS 5.5 - MEDIUM
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
SINGLE
Confidentiality impact
NONE
Integrity impact
PARTIAL
Availability impact
PARTIAL
network
low complexity
ethereum
CWE-682

Summary

Go Ethereum, or "Geth", is the official Golang implementation of the Ethereum protocol. This is a Consensus vulnerability in Geth before version 1.9.17 which can be used to cause a chain-split where vulnerable nodes reject the canonical chain. Geth's pre-compiled dataCopy (at 0x00...04) contract did a shallow copy on invocation. An attacker could deploy a contract that writes X to an EVM memory region R, then calls 0x00..04 with R as an argument, then overwrites R to Y, and finally invokes the RETURNDATACOPY opcode. When this contract is invoked, a consensus-compliant node would push X on the EVM stack, whereas Geth would push Y. This is fixed in version 1.9.17.

Vulnerable Configurations

Part Description Count
Application
Ethereum
152

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Attack through Shared Data
    An attacker exploits a data structure shared between multiple applications or an application pool to affect application behavior. Data may be shared between multiple applications or between multiple threads of a single application. Data sharing is usually accomplished through mutual access to a single memory location. If an attacker can manipulate this shared data (usually by co-opting one of the applications or threads) the other applications or threads using the shared data will often continue to trust the validity of the compromised shared data and use it in their calculations. This can result in invalid trust assumptions, corruption of additional data through the normal operations of the other users of the shared data, or even cause a crash or compromise of the sharing applications.
  • Integer Attacks
    An attacker takes advantage of the structure of integer variables to cause these variables to assume values that are not expected by an application. For example, adding one to the largest positive integer in a signed integer variable results in a negative number. Negative numbers may be illegal in an application and the application may prevent an attacker from providing them directly, but the application may not consider that adding two positive numbers can create a negative number do to the structure of integer storage formats.
  • Pointer Attack
    This attack involves an attacker manipulating a pointer within a target application resulting in the application accessing an unintended memory location. This can result in the crashing of the application or, for certain pointer values, access to data that would not normally be possible or the execution of arbitrary code. Since pointers are simply integer variables, Integer Attacks may often be used in Pointer Attacks.