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    Dashboard / CVE / CVE-2021-29431

    CVE-2021-29431

    Sydent is a reference Matrix identity server. Sydent can be induced to send HTTP GET requests to internal systems, due to lack of parameter validation or IP address blacklisting. It is not possible to exfiltrate data or control request headers, but it might be possible to use the attack to perform an internal port enumeration. This issue has been addressed in in 9e57334, 8936925, 3d531ed, 0f00412. A potential workaround would be to use a firewall to ensure that Sydent cannot reach internal HTTP resources.

    Published:Apr 15, 2021
    Last Modified:Nov 21, 2024
    EPS:Apr 15, 2021
    EPSS Score:0.00303
    CVSS Score:7.7

    Affected Products

    Vendor
    Matrix
    Product
    Sydent

    Exploits

    No exploit reference

    Common Attack Pattern Enumeration and Classification (CAPEC)

    CAPEC-10 Buffer Overflow via Environment Variables
    CAPEC-101 Server Side Include (SSI) Injection
    CAPEC-104 Cross Zone Scripting
    CAPEC-108 Command Line Execution through SQL Injection
    CAPEC-109 Object Relational Mapping Injection
    CAPEC-110 SQL Injection through SOAP Parameter Tampering
    CAPEC-120 Double Encoding
    CAPEC-13 Subverting Environment Variable Values
    CAPEC-135 Format String Injection
    CAPEC-136 LDAP Injection
    CAPEC-14 Client-side Injection-induced Buffer Overflow
    CAPEC-153 Input Data Manipulation
    CAPEC-182 Flash Injection
    CAPEC-209 XSS Using MIME Type Mismatch
    CAPEC-22 Exploiting Trust in Client
    CAPEC-23 File Content Injection
    CAPEC-230 Serialized Data with Nested Payloads
    CAPEC-231 Oversized Serialized Data Payloads
    CAPEC-24 Filter Failure through Buffer Overflow
    CAPEC-250 XML Injection
    CAPEC-261 Fuzzing for garnering other adjacent user/sensitive data
    CAPEC-267 Leverage Alternate Encoding
    CAPEC-28 Fuzzing
    CAPEC-3 Using Leading 'Ghost' Character Sequences to Bypass Input Filters
    CAPEC-31 Accessing/Intercepting/Modifying HTTP Cookies
    CAPEC-42 MIME Conversion
    CAPEC-43 Exploiting Multiple Input Interpretation Layers
    CAPEC-45 Buffer Overflow via Symbolic Links
    CAPEC-46 Overflow Variables and Tags
    CAPEC-47 Buffer Overflow via Parameter Expansion
    CAPEC-473 Signature Spoof
    CAPEC-52 Embedding NULL Bytes
    CAPEC-53 Postfix, Null Terminate, and Backslash
    CAPEC-588 DOM-Based XSS
    CAPEC-63 Cross-Site Scripting (XSS)
    CAPEC-64 Using Slashes and URL Encoding Combined to Bypass Validation Logic
    CAPEC-664 Server Side Request Forgery
    CAPEC-67 String Format Overflow in syslog()
    CAPEC-7 Blind SQL Injection
    CAPEC-71 Using Unicode Encoding to Bypass Validation Logic
    CAPEC-72 URL Encoding
    CAPEC-73 User-Controlled Filename
    CAPEC-78 Using Escaped Slashes in Alternate Encoding
    CAPEC-79 Using Slashes in Alternate Encoding
    CAPEC-8 Buffer Overflow in an API Call
    CAPEC-80 Using UTF-8 Encoding to Bypass Validation Logic
    CAPEC-81 Web Server Logs Tampering
    CAPEC-83 XPath Injection
    CAPEC-85 AJAX Footprinting
    CAPEC-88 OS Command Injection
    CAPEC-9 Buffer Overflow in Local Command-Line Utilities

    Related CVEs

    CVE-2023-38686 (CVSS 9.3) — Sydent is an identity server for the Matrix communications protocol. Prior to version 2.5.6, if configured to …
    CVE-2021-29432 (CVSS 5.3) — Sydent is a reference matrix identity server. A malicious user could abuse Sydent to send out arbitrary emails…
    CVE-2021-29430 (CVSS 7.5) — Sydent is a reference Matrix identity server. Sydent does not limit the size of requests it receives from HTTP…
    CVE-2021-29433 (CVSS 4.3) — Sydent is a reference Matrix identity server. In Sydent versions 2.2.0 and prior, sissing input validation of …
    CVE-2019-11842 (CVSS 7.5) — An issue was discovered in Matrix Sydent before 1.0.3 and Synapse before 0.99.3.1. Random number generation is…
    CVE-2019-11340 (CVSS 5.9) — util/emailutils.py in Matrix Sydent before 1.0.2 mishandles registration restrictions that are based on e-mail…

    References

    https://github.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310a
    https://github.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3
    https://github.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00a
    https://github.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5f
    https://github.com/matrix-org/sydent/releases/tag/v2.3.0
    https://github.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4
    https://pypi.org/project/matrix-sydent/
    https://github.com/matrix-org/sydent/commit/0f00412017f25619bc36c264b29ea96808bf310a
    https://github.com/matrix-org/sydent/commit/3d531ed50d2fd41ac387f36d44d3fb2c62dd22d3
    https://github.com/matrix-org/sydent/commit/8936925f561b0c352c2fa922d5097d7245aad00a
    https://github.com/matrix-org/sydent/commit/9e573348d81df8191bbe8c266c01999c9d57cd5f
    https://github.com/matrix-org/sydent/releases/tag/v2.3.0
    https://github.com/matrix-org/sydent/security/advisories/GHSA-9jhm-8m8c-c3f4
    https://pypi.org/project/matrix-sydent/

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High