CVE-2020-26263
Tlslite-ng RSA PKCS#1 v1.5 Decryption Side-Channel Information Leak
Description
tlslite-ng is an open source python library that implements SSL and TLS cryptographic protocols. In tlslite-ng before versions 0.7.6 and 0.8.0-alpha39, the code that performs decryption and padding check in RSA PKCS#1 v1.5 decryption is data dependant. In particular, the code has multiple ways in which it leaks information about the decrypted ciphertext. It aborts as soon as the plaintext doesn't start with 0x00, 0x02. All TLS servers that enable RSA key exchange as well as applications that use the RSA decryption API directly are vulnerable. This is patched in versions 0.7.6 and 0.8.0-alpha39. Note: the patches depend on Python processing the individual bytes in side-channel free manner, this is known to not the case (see reference). As such, users that require side-channel resistance are recommended to use different TLS implementations, as stated in the security policy of tlslite-ng.
INFO
Published Date :
Dec. 21, 2020, 5:15 p.m.
Last Modified :
Dec. 23, 2020, 4:09 p.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
3.6
Exploitability Score :
3.9
Public PoC/Exploit Available at Github
CVE-2020-26263 has a 4 public PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2020-26263.
| URL | Resource |
|---|---|
| https://github.com/tlsfuzzer/tlslite-ng/commit/c28d6d387bba59d8bd5cb3ba15edc42edf54b368 | Patch Third Party Advisory |
| https://github.com/tlsfuzzer/tlslite-ng/pull/438 | Patch Third Party Advisory |
| https://github.com/tlsfuzzer/tlslite-ng/pull/439 | Patch Third Party Advisory |
| https://github.com/tlsfuzzer/tlslite-ng/security/advisories/GHSA-wvcv-832q-fjg7 | Exploit Patch Third Party Advisory |
| https://pypi.org/project/tlslite-ng/ | Product Third Party Advisory |
| https://securitypitfalls.wordpress.com/2018/08/03/constant-time-compare-in-python/ | Exploit Third Party Advisory |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
tlslite-ng
Makefile Python Shell HTML
None
Makefile Python Shell HTML
https://github.com/tomato42/tlslite-ng.git
Makefile Python Shell HTML
TLS implementation in pure python, focused on interoperability testing
ssl tls security-protocol https https-client tls12 tls13 rsa ecdsa
Makefile Python Shell HTML
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2020-26263 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2020-26263 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Initial Analysis by [email protected]
Dec. 23, 2020
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:N/A:N) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Changed Reference Type https://github.com/tlsfuzzer/tlslite-ng/commit/c28d6d387bba59d8bd5cb3ba15edc42edf54b368 No Types Assigned https://github.com/tlsfuzzer/tlslite-ng/commit/c28d6d387bba59d8bd5cb3ba15edc42edf54b368 Patch, Third Party Advisory Changed Reference Type https://github.com/tlsfuzzer/tlslite-ng/pull/438 No Types Assigned https://github.com/tlsfuzzer/tlslite-ng/pull/438 Patch, Third Party Advisory Changed Reference Type https://github.com/tlsfuzzer/tlslite-ng/pull/439 No Types Assigned https://github.com/tlsfuzzer/tlslite-ng/pull/439 Patch, Third Party Advisory Changed Reference Type https://github.com/tlsfuzzer/tlslite-ng/security/advisories/GHSA-wvcv-832q-fjg7 No Types Assigned https://github.com/tlsfuzzer/tlslite-ng/security/advisories/GHSA-wvcv-832q-fjg7 Exploit, Patch, Third Party Advisory Changed Reference Type https://pypi.org/project/tlslite-ng/ No Types Assigned https://pypi.org/project/tlslite-ng/ Product, Third Party Advisory Changed Reference Type https://securitypitfalls.wordpress.com/2018/08/03/constant-time-compare-in-python/ No Types Assigned https://securitypitfalls.wordpress.com/2018/08/03/constant-time-compare-in-python/ Exploit, Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:tlslite-ng_project:tlslite-ng:*:*:*:*:*:*:*:* versions up to (excluding) 0.7.6 *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha1:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha10:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha11:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha12:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha13:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha14:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha15:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha16:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha17:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha18:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha19:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha2:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha20:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha21:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha22:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha23:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha24:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha25:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha26:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha27:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha28:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha29:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha3:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha30:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha31:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha32:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha33:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha34:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha35:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha36:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha37:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha38:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha4:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha5:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha6:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha7:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha8:*:*:*:*:*:* *cpe:2.3:a:tlslite-ng_project:tlslite-ng:0.8.0:alpha9:*:*:*:*:*:*
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2020-26263 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2020-26263
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.30 }} 0.04%
score
0.69856
percentile