Vulnerability-Lookup

CNVD-2021-71262

Vulnerability from cnvd - Published: 2021-09-15

Title

libssh缓冲区溢出漏洞（CNVD-2021-71262）

Description

Libssh是Libssh组织的一个用于访问SSH服务的C语言开发包，它能够执行远程命令、文件传输，同时为远程的程序提供安全的传输通道。 libssh存在缓冲区溢出漏洞，该漏洞源于libssh 允许在密钥重新交换操作中改变密钥交换方法。改变密钥交换方法时，如果采用不同长度的 hash ，将会导致缓冲区错误。目前没有详细的漏洞细节提供。

Severity

中

Patch Name

libssh缓冲区溢出漏洞（CNVD-2021-71262）的补丁

Patch Description

Formal description

目前厂商已发布升级补丁以修复漏洞，补丁获取链接： https://www.libssh.org/2021/08/26/libssh-0-9-6-security-release/

Reference

https://nvd.nist.gov/vuln/detail/CVE-2021-3634

Impacted products

Name
libssh libssh

Show details on source website

JSON

To clipboard

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  "cves": {
    "cve": {
      "cveNumber": "CVE-2021-3634"
    }
  },
  "description": "Libssh\u662fLibssh\u7ec4\u7ec7\u7684\u4e00\u4e2a\u7528\u4e8e\u8bbf\u95eeSSH\u670d\u52a1\u7684C\u8bed\u8a00\u5f00\u53d1\u5305\uff0c\u5b83\u80fd\u591f\u6267\u884c\u8fdc\u7a0b\u547d\u4ee4\u3001\u6587\u4ef6\u4f20\u8f93\uff0c\u540c\u65f6\u4e3a\u8fdc\u7a0b\u7684\u7a0b\u5e8f\u63d0\u4f9b\u5b89\u5168\u7684\u4f20\u8f93\u901a\u9053\u3002\n\nlibssh\u5b58\u5728\u7f13\u51b2\u533a\u6ea2\u51fa\u6f0f\u6d1e\uff0c\u8be5\u6f0f\u6d1e\u6e90\u4e8elibssh \u5141\u8bb8\u5728\u5bc6\u94a5\u91cd\u65b0\u4ea4\u6362\u64cd\u4f5c\u4e2d\u6539\u53d8\u5bc6\u94a5\u4ea4\u6362\u65b9\u6cd5\u3002\u6539\u53d8\u5bc6\u94a5\u4ea4\u6362\u65b9\u6cd5\u65f6\uff0c\u5982\u679c\u91c7\u7528\u4e0d\u540c\u957f\u5ea6\u7684 hash \uff0c\u5c06\u4f1a\u5bfc\u81f4\u7f13\u51b2\u533a\u9519\u8bef\u3002\u76ee\u524d\u6ca1\u6709\u8be6\u7ec6\u7684\u6f0f\u6d1e\u7ec6\u8282\u63d0\u4f9b\u3002",
  "formalWay": "\u76ee\u524d\u5382\u5546\u5df2\u53d1\u5e03\u5347\u7ea7\u8865\u4e01\u4ee5\u4fee\u590d\u6f0f\u6d1e\uff0c\u8865\u4e01\u83b7\u53d6\u94fe\u63a5\uff1a\r\nhttps://www.libssh.org/2021/08/26/libssh-0-9-6-security-release/",
  "isEvent": "\u901a\u7528\u8f6f\u786c\u4ef6\u6f0f\u6d1e",
  "number": "CNVD-2021-71262",
  "openTime": "2021-09-15",
  "patchDescription": "Libssh\u662fLibssh\u7ec4\u7ec7\u7684\u4e00\u4e2a\u7528\u4e8e\u8bbf\u95eeSSH\u670d\u52a1\u7684C\u8bed\u8a00\u5f00\u53d1\u5305\uff0c\u5b83\u80fd\u591f\u6267\u884c\u8fdc\u7a0b\u547d\u4ee4\u3001\u6587\u4ef6\u4f20\u8f93\uff0c\u540c\u65f6\u4e3a\u8fdc\u7a0b\u7684\u7a0b\u5e8f\u63d0\u4f9b\u5b89\u5168\u7684\u4f20\u8f93\u901a\u9053\u3002\r\n\r\nlibssh\u5b58\u5728\u7f13\u51b2\u533a\u6ea2\u51fa\u6f0f\u6d1e\uff0c\u8be5\u6f0f\u6d1e\u6e90\u4e8elibssh \u5141\u8bb8\u5728\u5bc6\u94a5\u91cd\u65b0\u4ea4\u6362\u64cd\u4f5c\u4e2d\u6539\u53d8\u5bc6\u94a5\u4ea4\u6362\u65b9\u6cd5\u3002\u6539\u53d8\u5bc6\u94a5\u4ea4\u6362\u65b9\u6cd5\u65f6\uff0c\u5982\u679c\u91c7\u7528\u4e0d\u540c\u957f\u5ea6\u7684 hash \uff0c\u5c06\u4f1a\u5bfc\u81f4\u7f13\u51b2\u533a\u9519\u8bef\u3002\u76ee\u524d\u6ca1\u6709\u8be6\u7ec6\u7684\u6f0f\u6d1e\u7ec6\u8282\u63d0\u4f9b\u3002\u76ee\u524d\uff0c\u4f9b\u5e94\u5546\u53d1\u5e03\u4e86\u5b89\u5168\u516c\u544a\u53ca\u76f8\u5173\u8865\u4e01\u4fe1\u606f\uff0c\u4fee\u590d\u4e86\u6b64\u6f0f\u6d1e\u3002",
  "patchName": "libssh\u7f13\u51b2\u533a\u6ea2\u51fa\u6f0f\u6d1e\uff08CNVD-2021-71262\uff09\u7684\u8865\u4e01",
  "products": {
    "product": "libssh libssh"
  },
  "referenceLink": "https://nvd.nist.gov/vuln/detail/CVE-2021-3634",
  "serverity": "\u4e2d",
  "submitTime": "2021-09-02",
  "title": "libssh\u7f13\u51b2\u533a\u6ea2\u51fa\u6f0f\u6d1e\uff08CNVD-2021-71262\uff09"
}

CVE-2021-3634 (GCVE-0-2021-3634)

Vulnerability from cvelistv5 – Published: 2021-08-31 00:00 – Updated: 2024-08-03 17:01

Summary

A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other session_id. Initially, both of them are the same, but after key re-exchange, previous session_id is kept and used as an input to new secret_hash. Historically, both of these buffers had shared length variable, which worked as long as these buffers were same. But the key re-exchange operation can also change the key exchange method, which can be based on hash of different size, eventually creating "secret_hash" of different size than the session_id has. This becomes an issue when the session_id memory is zeroed or when it is used again during second key re-exchange.

Severity

No CVSS data available.

CWE

CWE-787

Assigner

redhat redhat root

References

8 references

URL	Tags
https://bugzilla.redhat.com/show_bug.cgi?id=1978810
https://www.debian.org/security/2021/dsa-4965	vendor-advisory
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisory
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisory
https://lists.fedoraproject.org/archives/list/pac…	vendor-advisory
https://www.oracle.com/security-alerts/cpujan2022.html
https://security.netapp.com/advisory/ntap-2021100…
https://security.gentoo.org/glsa/202312-05	vendor-advisory

Impacted products

1 product

Vendor	Product	Version
n/a	libssh	Affected: libssh 0.9.6

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T17:01:07.562Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
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        "references": [
          {
            "tags": [
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            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1978810"
          },
          {
            "name": "DSA-4965",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://www.debian.org/security/2021/dsa-4965"
          },
          {
            "name": "FEDORA-2021-ec797b6a96",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVWAAB2XMKEUMPMDALINKAA4U2QM4LNG/"
          },
          {
            "name": "FEDORA-2021-288925ac19",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JKYD3ZRAMDAQX3ZW6THHUF3GXN7FF6B4/"
          },
          {
            "name": "FEDORA-2021-f2a020a065",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DRK67AJCWYYVAGF5SGAHNZXCX3PN3ZFP/"
          },
          {
            "tags": [
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            "url": "https://www.oracle.com/security-alerts/cpujan2022.html"
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          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20211004-0003/"
          },
          {
            "name": "GLSA-202312-05",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202312-05"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "libssh",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "libssh 0.9.6"
            }
          ]
        }
      ],
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        {
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          "value": "A flaw has been found in libssh in versions prior to 0.9.6. The SSH protocol keeps track of two shared secrets during the lifetime of the session. One of them is called secret_hash and the other session_id. Initially, both of them are the same, but after key re-exchange, previous session_id is kept and used as an input to new secret_hash. Historically, both of these buffers had shared length variable, which worked as long as these buffers were same. But the key re-exchange operation can also change the key exchange method, which can be based on hash of different size, eventually creating \"secret_hash\" of different size than the session_id has. This becomes an issue when the session_id memory is zeroed or when it is used again during second key re-exchange."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
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              "description": "CWE-787",
              "lang": "en",
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        "dateUpdated": "2023-12-22T10:06:14.732Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
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      "references": [
        {
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1978810"
        },
        {
          "name": "DSA-4965",
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          ],
          "url": "https://www.debian.org/security/2021/dsa-4965"
        },
        {
          "name": "FEDORA-2021-ec797b6a96",
          "tags": [
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          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SVWAAB2XMKEUMPMDALINKAA4U2QM4LNG/"
        },
        {
          "name": "FEDORA-2021-288925ac19",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JKYD3ZRAMDAQX3ZW6THHUF3GXN7FF6B4/"
        },
        {
          "name": "FEDORA-2021-f2a020a065",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DRK67AJCWYYVAGF5SGAHNZXCX3PN3ZFP/"
        },
        {
          "url": "https://www.oracle.com/security-alerts/cpujan2022.html"
        },
        {
          "url": "https://security.netapp.com/advisory/ntap-20211004-0003/"
        },
        {
          "name": "GLSA-202312-05",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.gentoo.org/glsa/202312-05"
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    "datePublished": "2021-08-31T00:00:00.000Z",
    "dateReserved": "2021-07-02T00:00:00.000Z",
    "dateUpdated": "2024-08-03T17:01:07.562Z",
    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
  "dataVersion": "5.1"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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CNVD-2021-71262

CVE-2021-3634 (GCVE-0-2021-3634)

Tags

Sightings

Nomenclature

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