VDB-125894 · CVE-2018-17877 · GCVE-0-2018-17877

Greedy 599 extcodesize Smart Contract weak prng

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.4	$0-$5k	0.00

Summaryinfo

A vulnerability was found in Greedy 599. It has been declared as critical. Affected is the function extcodesize. Such manipulation as part of Smart Contract leads to weak prng. This vulnerability is traded as CVE-2018-17877. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Greedy 599 (version now known). Affected by this issue is the function extcodesize. The manipulation as part of a Smart Contract leads to a weak prng vulnerability. Using CWE to declare the problem leads to CWE-338. The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong. Impacted is confidentiality, integrity, and availability. CVE summarizes:

A lottery smart contract implementation for Greedy 599, an Ethereum gambling game, generates a random value that is predictable via an external contract call. The developer used the extcodesize() function to prevent a malicious contract from being called, but the attacker can bypass it by writing the core code in the constructor of their exploit code. Therefore, it allows attackers to always win and get rewards.

The bug was discovered 10/08/2018. The weakness was shared 10/23/2018 (Website). The advisory is available at github.com. This vulnerability is handled as CVE-2018-17877 since 10/01/2018. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1600.001 by the MITRE ATT&CK project.

The vulnerability was handled as a non-public zero-day exploit for at least 15 days. During that time the estimated underground price was around $0-$5k.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Name

Greedy 599

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.4
VulDB Meta Temp Score: 7.4

VulDB Base Score: 7.3
VulDB Temp Score: 7.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Weak prng
CWE: CWE-338 / CWE-331 / CWE-330
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔍

Timelineinfo

10/01/2018 🔍
10/08/2018 +7 days 🔍
10/23/2018 +14 days 🔍
10/23/2018 +0 days 🔍
10/24/2018 +1 days 🔍
04/06/2020 +530 days 🔍

Sourcesinfo

Advisory: github.com
Status: Not defined

CVE: CVE-2018-17877 (🔍)
GCVE (CVE): GCVE-0-2018-17877
GCVE (VulDB): GCVE-100-125894

Entryinfo

Created: 10/24/2018 08:18
Updated: 04/06/2020 09:56
Changes: 10/24/2018 08:18 (55), 04/06/2020 09:56 (1)
Complete: 🔍
Cache ID: 216::103