CVE-2021-42574
Oracle Unicode Bidirectional Algorithm Code Injection Vulnerability
Description
An issue was discovered in the Bidirectional Algorithm in the Unicode Specification through 14.0. It permits the visual reordering of characters via control sequences, which can be used to craft source code that renders different logic than the logical ordering of tokens ingested by compilers and interpreters. Adversaries can leverage this to encode source code for compilers accepting Unicode such that targeted vulnerabilities are introduced invisibly to human reviewers. NOTE: the Unicode Consortium offers the following alternative approach to presenting this concern. An issue is noted in the nature of international text that can affect applications that implement support for The Unicode Standard and the Unicode Bidirectional Algorithm (all versions). Due to text display behavior when text includes left-to-right and right-to-left characters, the visual order of tokens may be different from their logical order. Additionally, control characters needed to fully support the requirements of bidirectional text can further obfuscate the logical order of tokens. Unless mitigated, an adversary could craft source code such that the ordering of tokens perceived by human reviewers does not match what will be processed by a compiler/interpreter/etc. The Unicode Consortium has documented this class of vulnerability in its document, Unicode Technical Report #36, Unicode Security Considerations. The Unicode Consortium also provides guidance on mitigations for this class of issues in Unicode Technical Standard #39, Unicode Security Mechanisms, and in Unicode Standard Annex #31, Unicode Identifier and Pattern Syntax. Also, the BIDI specification allows applications to tailor the implementation in ways that can mitigate misleading visual reordering in program text; see HL4 in Unicode Standard Annex #9, Unicode Bidirectional Algorithm.
INFO
Published Date :
Nov. 1, 2021, 4:15 a.m.
Last Modified :
Aug. 4, 2024, 4:16 a.m.
Source :
[email protected]
Remotely Exploitable :
Yes !
Impact Score :
6.0
Exploitability Score :
1.6
Public PoC/Exploit Available at Github
CVE-2021-42574 has a 21 public PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
Affected Products
The following products are affected by CVE-2021-42574
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
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-2021-42574.
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).
All CVE - PoC in GitHub
poc proofofconcept tester allcve cvegithub cvenew cvepoc cveupdate
None
None
asp-net-core csharp docker dockerfile javascript react webapi docker-compose
C# Dockerfile HTML JavaScript CSS
None
Bittide aegir simulator
bittide
Rust Python Verilog Shell
POC of CVE-2021-42574 for solidity and solc compiler
Python Solidity
None
Map Vulnerabilities into Different Layers of the Container Image
Python
None
None
C
Provides custom lint rules developed by Bottle Rocket Studios to help keep our code cleaner, detect and mitigate possible security issues, and allow us to write rules around best practices and usage as necessary in the future
Kotlin Shell
None
Rust
A GitHub Action to find Unicode control characters using the Red Hat diagnostic tool https://access.redhat.com/security/vulnerabilities/RHSB-2021-007 to detect RHSB-2021-007 Trojan source attacks (CVE-2021-42574,CVE-2021-42694)
Dockerfile Shell Python
Trojan Source Maven Plugin
Java
Checks your files for existence of Unicode BIDI characters which can be misused for supply chain attacks. See CVE-2021-42574
security rust cve-2021-42574 unicode-characters docker supply-chain-attacks
Dockerfile Rust JavaScript
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-42574 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-42574 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]
Aug. 04, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
Jun. 11, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
May. 17, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
Apr. 11, 2024
Action Type Old Value New Value -
CVE Modified by [email protected]
Mar. 21, 2024
Action Type Old Value New Value Added Tag MITRE disputed -
CVE Modified by [email protected]
Nov. 07, 2023
Action Type Old Value New Value Changed Description ** DISPUTED ** An issue was discovered in the Bidirectional Algorithm in the Unicode Specification through 14.0. It permits the visual reordering of characters via control sequences, which can be used to craft source code that renders different logic than the logical ordering of tokens ingested by compilers and interpreters. Adversaries can leverage this to encode source code for compilers accepting Unicode such that targeted vulnerabilities are introduced invisibly to human reviewers. NOTE: the Unicode Consortium offers the following alternative approach to presenting this concern. An issue is noted in the nature of international text that can affect applications that implement support for The Unicode Standard and the Unicode Bidirectional Algorithm (all versions). Due to text display behavior when text includes left-to-right and right-to-left characters, the visual order of tokens may be different from their logical order. Additionally, control characters needed to fully support the requirements of bidirectional text can further obfuscate the logical order of tokens. Unless mitigated, an adversary could craft source code such that the ordering of tokens perceived by human reviewers does not match what will be processed by a compiler/interpreter/etc. The Unicode Consortium has documented this class of vulnerability in its document, Unicode Technical Report #36, Unicode Security Considerations. The Unicode Consortium also provides guidance on mitigations for this class of issues in Unicode Technical Standard #39, Unicode Security Mechanisms, and in Unicode Standard Annex #31, Unicode Identifier and Pattern Syntax. Also, the BIDI specification allows applications to tailor the implementation in ways that can mitigate misleading visual reordering in program text; see HL4 in Unicode Standard Annex #9, Unicode Bidirectional Algorithm. An issue was discovered in the Bidirectional Algorithm in the Unicode Specification through 14.0. It permits the visual reordering of characters via control sequences, which can be used to craft source code that renders different logic than the logical ordering of tokens ingested by compilers and interpreters. Adversaries can leverage this to encode source code for compilers accepting Unicode such that targeted vulnerabilities are introduced invisibly to human reviewers. NOTE: the Unicode Consortium offers the following alternative approach to presenting this concern. An issue is noted in the nature of international text that can affect applications that implement support for The Unicode Standard and the Unicode Bidirectional Algorithm (all versions). Due to text display behavior when text includes left-to-right and right-to-left characters, the visual order of tokens may be different from their logical order. Additionally, control characters needed to fully support the requirements of bidirectional text can further obfuscate the logical order of tokens. Unless mitigated, an adversary could craft source code such that the ordering of tokens perceived by human reviewers does not match what will be processed by a compiler/interpreter/etc. The Unicode Consortium has documented this class of vulnerability in its document, Unicode Technical Report #36, Unicode Security Considerations. The Unicode Consortium also provides guidance on mitigations for this class of issues in Unicode Technical Standard #39, Unicode Security Mechanisms, and in Unicode Standard Annex #31, Unicode Identifier and Pattern Syntax. Also, the BIDI specification allows applications to tailor the implementation in ways that can mitigate misleading visual reordering in program text; see HL4 in Unicode Standard Annex #9, Unicode Bidirectional Algorithm. Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QUPA37D57VPTDLSXOOGF4UXUEADOC4PQ/ [No types assigned] Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LQNTFF24ROHLVPLUOEISBN3F7QM27L4U/ [No types assigned] Added Reference MITRE https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/IH2RG5YTR6ZZOLUV3EUPZEIJR7XHJLVD/ [No types assigned] Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/QUPA37D57VPTDLSXOOGF4UXUEADOC4PQ/ Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/LQNTFF24ROHLVPLUOEISBN3F7QM27L4U/ Removed Reference MITRE https://lists.fedoraproject.org/archives/list/[email protected]/message/IH2RG5YTR6ZZOLUV3EUPZEIJR7XHJLVD/ -
Modified Analysis by [email protected]
Oct. 25, 2022
Action Type Old Value New Value Changed Reference Type https://security.gentoo.org/glsa/202210-09 No Types Assigned https://security.gentoo.org/glsa/202210-09 Third Party Advisory Changed Reference Type https://www.starwindsoftware.com/security/sw-20220804-0002/ No Types Assigned https://www.starwindsoftware.com/security/sw-20220804-0002/ Third Party Advisory Added CPE Configuration OR *cpe:2.3:a:starwindsoftware:starwind_virtual_san:v8r13:14398:*:*:*:*:*:* -
CVE Modified by [email protected]
Oct. 16, 2022
Action Type Old Value New Value Added Reference https://security.gentoo.org/glsa/202210-09 [No Types Assigned] -
CVE Modified by [email protected]
Oct. 11, 2022
Action Type Old Value New Value Added Reference https://www.starwindsoftware.com/security/sw-20220804-0002/ [No Types Assigned] -
Modified Analysis by [email protected]
Sep. 03, 2022
Action Type Old Value New Value Changed Reference Type https://www.unicode.org/reports/tr31/ No Types Assigned https://www.unicode.org/reports/tr31/ Technical Description, Vendor Advisory Changed Reference Type https://www.unicode.org/reports/tr36/ No Types Assigned https://www.unicode.org/reports/tr36/ Technical Description, Vendor Advisory Changed Reference Type https://www.unicode.org/reports/tr39/ No Types Assigned https://www.unicode.org/reports/tr39/ Technical Description, Vendor Advisory Changed Reference Type https://www.unicode.org/reports/tr9/tr9-44.html#HL4 No Types Assigned https://www.unicode.org/reports/tr9/tr9-44.html#HL4 Technical Description, Vendor Advisory -
CVE Modified by [email protected]
May. 12, 2022
Action Type Old Value New Value Changed Description An issue was discovered in the Bidirectional Algorithm in the Unicode Specification through 14.0. It permits the visual reordering of characters via control sequences, which can be used to craft source code that renders different logic than the logical ordering of tokens ingested by compilers and interpreters. Adversaries can leverage this to encode source code for compilers accepting Unicode such that targeted vulnerabilities are introduced invisibly to human reviewers. ** DISPUTED ** An issue was discovered in the Bidirectional Algorithm in the Unicode Specification through 14.0. It permits the visual reordering of characters via control sequences, which can be used to craft source code that renders different logic than the logical ordering of tokens ingested by compilers and interpreters. Adversaries can leverage this to encode source code for compilers accepting Unicode such that targeted vulnerabilities are introduced invisibly to human reviewers. NOTE: the Unicode Consortium offers the following alternative approach to presenting this concern. An issue is noted in the nature of international text that can affect applications that implement support for The Unicode Standard and the Unicode Bidirectional Algorithm (all versions). Due to text display behavior when text includes left-to-right and right-to-left characters, the visual order of tokens may be different from their logical order. Additionally, control characters needed to fully support the requirements of bidirectional text can further obfuscate the logical order of tokens. Unless mitigated, an adversary could craft source code such that the ordering of tokens perceived by human reviewers does not match what will be processed by a compiler/interpreter/etc. The Unicode Consortium has documented this class of vulnerability in its document, Unicode Technical Report #36, Unicode Security Considerations. The Unicode Consortium also provides guidance on mitigations for this class of issues in Unicode Technical Standard #39, Unicode Security Mechanisms, and in Unicode Standard Annex #31, Unicode Identifier and Pattern Syntax. Also, the BIDI specification allows applications to tailor the implementation in ways that can mitigate misleading visual reordering in program text; see HL4 in Unicode Standard Annex #9, Unicode Bidirectional Algorithm. Added Reference https://www.unicode.org/reports/tr36/ [No Types Assigned] Added Reference https://www.unicode.org/reports/tr9/tr9-44.html#HL4 [No Types Assigned] Added Reference https://www.unicode.org/reports/tr31/ [No Types Assigned] Added Reference https://www.unicode.org/reports/tr39/ [No Types Assigned] -
Modified Analysis by [email protected]
Nov. 30, 2021
Action Type Old Value New Value Changed Reference Type https://www.scyon.nl/post/trojans-in-your-source-code No Types Assigned https://www.scyon.nl/post/trojans-in-your-source-code Exploit, Mitigation, Third Party Advisory -
CVE Modified by [email protected]
Nov. 26, 2021
Action Type Old Value New Value Added Reference https://www.scyon.nl/post/trojans-in-your-source-code [No Types Assigned] -
Modified Analysis by [email protected]
Nov. 16, 2021
Action Type Old Value New Value Added CVSS V2 Metadata Victim must voluntarily interact with attack mechanism Removed CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:P/A:P) Added CVSS V2 NIST (AV:N/AC:H/Au:N/C:P/I:P/A:P) Removed CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CVSS V3.1 NIST AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H Changed Reference Type http://www.openwall.com/lists/oss-security/2021/11/02/10 No Types Assigned http://www.openwall.com/lists/oss-security/2021/11/02/10 Mailing List Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/IH2RG5YTR6ZZOLUV3EUPZEIJR7XHJLVD/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/IH2RG5YTR6ZZOLUV3EUPZEIJR7XHJLVD/ Mailing List, Third Party Advisory Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/LQNTFF24ROHLVPLUOEISBN3F7QM27L4U/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/LQNTFF24ROHLVPLUOEISBN3F7QM27L4U/ Mailing List, Third Party Advisory Changed Reference Type https://lists.fedoraproject.org/archives/list/[email protected]/message/QUPA37D57VPTDLSXOOGF4UXUEADOC4PQ/ No Types Assigned https://lists.fedoraproject.org/archives/list/[email protected]/message/QUPA37D57VPTDLSXOOGF4UXUEADOC4PQ/ Mailing List, Third Party Advisory Changed Reference Type https://www.kb.cert.org/vuls/id/999008 No Types Assigned https://www.kb.cert.org/vuls/id/999008 Third Party Advisory, US Government Resource Added CPE Configuration OR *cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* *cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* -
CVE Modified by [email protected]
Nov. 11, 2021
Action Type Old Value New Value Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/IH2RG5YTR6ZZOLUV3EUPZEIJR7XHJLVD/ [No Types Assigned] -
CVE Modified by [email protected]
Nov. 09, 2021
Action Type Old Value New Value Added Reference https://www.kb.cert.org/vuls/id/999008 [No Types Assigned] -
CVE Modified by [email protected]
Nov. 05, 2021
Action Type Old Value New Value Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/LQNTFF24ROHLVPLUOEISBN3F7QM27L4U/ [No Types Assigned] -
CVE Modified by [email protected]
Nov. 04, 2021
Action Type Old Value New Value Added Reference https://lists.fedoraproject.org/archives/list/[email protected]/message/QUPA37D57VPTDLSXOOGF4UXUEADOC4PQ/ [No Types Assigned] -
CVE Modified by [email protected]
Nov. 03, 2021
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2021/11/02/10 [No Types Assigned] -
Initial Analysis by [email protected]
Nov. 02, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:P/A:P) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Changed Reference Type http://www.openwall.com/lists/oss-security/2021/11/01/1 No Types Assigned http://www.openwall.com/lists/oss-security/2021/11/01/1 Exploit, Mailing List, Mitigation, Third Party Advisory Changed Reference Type http://www.openwall.com/lists/oss-security/2021/11/01/4 No Types Assigned http://www.openwall.com/lists/oss-security/2021/11/01/4 Exploit, Mailing List, Third Party Advisory Changed Reference Type http://www.openwall.com/lists/oss-security/2021/11/01/5 No Types Assigned http://www.openwall.com/lists/oss-security/2021/11/01/5 Mailing List, Third Party Advisory Changed Reference Type http://www.openwall.com/lists/oss-security/2021/11/01/6 No Types Assigned http://www.openwall.com/lists/oss-security/2021/11/01/6 Mailing List, Third Party Advisory Changed Reference Type http://www.unicode.org/versions/Unicode14.0.0/ No Types Assigned http://www.unicode.org/versions/Unicode14.0.0/ Release Notes, Vendor Advisory Changed Reference Type https://trojansource.codes No Types Assigned https://trojansource.codes Exploit, Technical Description, Third Party Advisory Added CWE NIST CWE-94 Added CPE Configuration OR *cpe:2.3:a:unicode:unicode:*:*:*:*:*:*:*:* versions up to (excluding) 14.0.0 -
CVE Modified by [email protected]
Nov. 01, 2021
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2021/11/01/5 [No Types Assigned] Added Reference http://www.openwall.com/lists/oss-security/2021/11/01/6 [No Types Assigned] -
CVE Modified by [email protected]
Nov. 01, 2021
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2021/11/01/4 [No Types Assigned] -
CVE Modified by [email protected]
Nov. 01, 2021
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2021/11/01/1 [No Types Assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-42574 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-2021-42574
weaknesses.
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
0.28 }} 0.02%
score
0.68576
percentile