| Vulnerability Name: | CVE-2021-42574 (CCN-212526) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Assigned: | 2021-10-31 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Published: | 2021-10-31 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Updated: | 2022-10-25 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Summary: | ** 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. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| CVSS v3 Severity: | 8.3 High (CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H) 7.2 High (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C)
8.5 High (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
7.4 High (REDHAT Temporal CVSS v3.1 Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C)
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| CVSS v2 Severity: | 5.1 Medium (CVSS v2 Vector: AV:N/AC:H/Au:N/C:P/I:P/A:P)
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| Vulnerability Type: | CWE-94 CWE-838 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Vulnerability Consequences: | Gain Access | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| References: | Source: MITRE Type: CNA CVE-2021-42574 Source: CCN Type: US-CERT VU#999008 Compilers permit Unicode control and homoglyph characters Source: MLIST Type: Exploit, Mailing List, Mitigation, Third Party Advisory [oss-security] 20211101 CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source code Source: MLIST Type: Exploit, Mailing List, Third Party Advisory [oss-security] 20211101 Re: CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source code Source: MLIST Type: Mailing List, Third Party Advisory [oss-security] 20211102 Re: CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source code Source: MLIST Type: Mailing List, Third Party Advisory [oss-security] 20211101 Trojan Source Attacks Source: MLIST Type: Mailing List [oss-security] 20211102 Re: Trojan Source Attacks Source: CCN Type: Unicode Web site Unicode 14.00 Source: MISC Type: Release Notes, Vendor Advisory http://www.unicode.org/versions/Unicode14.0.0/ Source: CCN Type: Rust Blog, Nov. 1, 2021 Security advisory for rustc (CVE-2021-42574) Source: CCN Type: Red Hat Bugzilla - Bug 2005819 (CVE-2021-42574) - CVE-2021-42574 Developer environment: Unicode's bidirectional (BiDi) override characters can cause trojan source attacks Source: XF Type: UNKNOWN unicode-cve202142574-code-exec(212526) Source: FEDORA Type: Mailing List, Third Party Advisory FEDORA-2021-443139f67c Source: FEDORA Type: Mailing List, Third Party Advisory FEDORA-2021-7ad3a01f6a Source: FEDORA Type: Mailing List, Third Party Advisory FEDORA-2021-0578e23912 Source: GENTOO Type: Third Party Advisory GLSA-202210-09 Source: MISC Type: Exploit, Technical Description, Third Party Advisory https://trojansource.codes Source: CCN Type: IBM Security Bulletin 6551876 (Cloud Pak for Security) Cloud Pak for Security uses packages that are vulnerable to multiple CVEs Source: CCN Type: IBM Security Bulletin 6568365 (QRadar Network Packet Capture) IBM QRadar Network Packet Capture is using components with known vulnerabilities Source: CCN Type: IBM Security Bulletin 6586492 (MQ Operator CD release) IBM MQ Operator and Queue manager container images are vulnerable to multiple vulnerabilities from expat, Golang Go, gcc, openssl and libxml. Source: CERT-VN Type: Third Party Advisory, US Government Resource VU#999008 Source: CCN Type: oss-sec Mailing List, Mon, 1 Nov 2021 01:01:46 +0100 CVE-2021-42574: rustc 1.56.0 and bidirectional-override codepoints in source code Source: CCN Type: Rust Web site Rust Source: MISC Type: Exploit, Mitigation, Third Party Advisory https://www.scyon.nl/post/trojans-in-your-source-code Source: MISC Type: Third Party Advisory https://www.starwindsoftware.com/security/sw-20220804-0002/ Source: MISC Type: Technical Description, Vendor Advisory https://www.unicode.org/reports/tr31/ Source: MISC Type: Technical Description, Vendor Advisory https://www.unicode.org/reports/tr36/ Source: MISC Type: Technical Description, Vendor Advisory https://www.unicode.org/reports/tr39/ Source: MISC Type: Technical Description, Vendor Advisory https://www.unicode.org/reports/tr9/tr9-44.html#HL4 Source: CCN Type: WhiteSource Vulnerability Database CVE-2021-42574 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Vulnerable Configuration: | Configuration 1: Configuration 2: Configuration 3: Configuration RedHat 1: Configuration RedHat 2: Configuration RedHat 3: Configuration RedHat 4: Configuration RedHat 5: Configuration RedHat 6: Configuration RedHat 7: Configuration RedHat 8: Configuration RedHat 9: Configuration RedHat 10: Configuration CCN 1:  Denotes that component is vulnerable | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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