CVE-2020-8244
Buffer Over-read vulnerability in bl (npm)
What is CVE-2020-8244 About?
This is a buffer over-read vulnerability in the 'bl' library that can lead to information disclosure. If specially crafted negative user input is processed by the 'consume()' function, it can corrupt the internal state of the BufferList. Successful exploitation is moderately difficult, requiring a specific input condition to trigger the sensitive memory exposure.
Affected Software
- bl
- >2.0.0, <2.2.1
- <1.2.3
- >3.0.0, <3.0.1
- >4.0.0, <4.0.3
Technical Details
A buffer over-read vulnerability exists in specific versions of the 'bl' library. When malformed user input, specifically a negative value, is passed to the 'consume()' function, it can corrupt the internal state of the BufferList object. This corruption tricks the BufferList into exposing uninitialized memory regions through subsequent regular '.slice()' calls. The attack vector involves supplying carefully crafted input that results in a negative 'consume()' argument, leading to internal state inconsistency and ultimately allowing an attacker to read arbitrary memory contents.
What is the Impact of CVE-2020-8244?
Successful exploitation may allow attackers to read sensitive information from uninitialized memory, potentially leading to information disclosure or further attacks if the exposed data can be used to bypass security measures.
What is the Exploitability of CVE-2020-8244?
Exploitation of this vulnerability requires an attacker to supply specially crafted negative user input that can be processed by the 'consume()' function. This suggests that the attacker needs a way to inject data into the application's input handling. There are no authentication requirements for triggering the initial condition, but it relies on external input. Privilege levels are not a direct factor as the vulnerability is in the library's internal state management. This is likely a remote vulnerability if the application exposes an interface for user input. The complexity lies in orchestrating the negative 'consume()' argument to corrupt the BufferList state and then using a subsequent '.slice()' call to read the sensitive memory. The ease of exploitation is dependent on how easily an attacker can control the input to the affected function.
What are the Known Public Exploits?
| PoC Author | Link | Commentary |
|---|---|---|
| No known exploits | ||
What are the Available Fixes for CVE-2020-8244?
About the Fix from Resolved Security
The patch for CVE-2020-8244 ensures that the BufferList's copy method returns only the portion of the buffer that was actually written to, preventing accidental exposure of uninitialized memory. It also normalizes and validates arguments for the consume method, avoiding potential misuse with negative or non-numeric values. This prevents attackers from accessing memory beyond the legitimate data boundaries, closing the information disclosure vulnerability.
Available Upgrade Options
- bl
- <1.2.3 → Upgrade to 1.2.3
- bl
- >2.0.0, <2.2.1 → Upgrade to 2.2.1
- bl
- >3.0.0, <3.0.1 → Upgrade to 3.0.1
- bl
- >4.0.0, <4.0.3 → Upgrade to 4.0.3
Struggling with dependency upgrades?
See how Resolved Security's drop-in replacements make it simple.
Book a demoAdditional Resources
- https://hackerone.com/reports/966347
- https://github.com/rvagg/bl/commit/8a8c13c880e2bef519133ea43e0e9b78b5d0c91e
- https://github.com/rvagg/bl/commit/dacc4ac7d5fcd6201bcf26fbd886951be9537466
- https://hackerone.com/reports/966347
- https://lists.debian.org/debian-lts-announce/2021/06/msg00028.html
- https://osv.dev/vulnerability/GHSA-pp7h-53gx-mx7r
- https://github.com/rvagg/bl/commit/d3e240e3b8ba4048d3c76ef5fb9dd1f8872d3190
- https://nvd.nist.gov/vuln/detail/CVE-2020-8244
- https://lists.debian.org/debian-lts-announce/2021/06/msg00028.html
What are Similar Vulnerabilities to CVE-2020-8244?
Similar Vulnerabilities: CVE-2023-38545 , CVE-2022-42916 , CVE-2021-37576 , CVE-2020-1971 , CVE-2023-34057
