hsec-2023-0011

Vulnerability from osv_haskell

Published

2025-11-14 14:45

Modified

2025-11-14 14:45

Summary

git-annex GPG decryption attack via compromised remote

Details

git-annex GPG decryption attack via compromised remote

A malicious server for a special remote could trick git-annex into decrypting a file that was encrypted to the user's GPG key. This attack could be used to expose encrypted data that was never stored in git-annex. Daniel Dent discovered this attack in collaboration with Joey Hess.

To perform this attack the attacker needs control of a server hosting an encrypted special remote used by the victim's git-annex repository. The attacker uses git annex addurl --relaxed with an innocuous URL, and waits for the user's git-annex to download it, and upload an (encrypted) copy to the special remote they also control. At some later point, when the user downloads the content from the special remote, the attacker instead sends them the content of the GPG-encrypted file that they wish to have decrypted in its place (which may have been exfiltrated from the victim's system via the attack described in HSEC-2023-0010 / CVE-2018-10857, or acquired by other means). Finally, the attacker drops their own copy of the original innocuous URL, and waits for the victim git-annex to send them the accidentially decrypted file.

The issue was fixed by making git-annex refuse to download encrypted content from special remotes, unless it knows the hash of the expected content. When the attacker provides some other GPG-encrypted content, it will fail the hash check and be discarded.

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "human_link": "https://github.com/haskell/security-advisories/tree/main/advisories/published/2023/HSEC-2023-0011.md",
        "osv": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export/2023/HSEC-2023-0011.json"
      },
      "package": {
        "ecosystem": "Hackage",
        "name": "git-annex"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.20110417"
            },
            {
              "fixed": "6.20180626"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2018-10859"
  ],
  "database_specific": {
    "home": "https://github.com/haskell/security-advisories",
    "osvs": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export",
    "repository": "https://github.com/haskell/security-advisories"
  },
  "details": "# *git-annex* GPG decryption attack via compromised remote\n\nA malicious server for a special remote could trick `git-annex` into\ndecrypting a file that was encrypted to the user\u0027s GPG key.  This\nattack could be used to expose encrypted data that was never stored\nin *git-annex*.  Daniel Dent discovered this attack in collaboration\nwith Joey Hess.\n\nTo perform this attack the attacker needs control of a server\nhosting an *encrypted* special remote used by the victim\u0027s\n*git-annex* repository.  The attacker uses `git annex addurl\n--relaxed` with an innocuous URL, and waits for the user\u0027s\n`git-annex` to download it, and upload an (encrypted) copy to the\nspecial remote they also control.  At some later point, when the\nuser downloads the content from the special remote, the attacker\ninstead sends them the content of the GPG-encrypted file that they\nwish to have decrypted in its place (which may have been exfiltrated\nfrom the victim\u0027s system via the attack described in\n**HSEC-2023-0010** / **CVE-2018-10857**, or acquired by other\nmeans).  Finally, the attacker drops their own copy of the original\ninnocuous URL, and waits for the victim `git-annex` to send them the\naccidentially decrypted file.\n\nThe issue was fixed by making `git-annex` refuse to download\nencrypted content from special remotes, unless it knows the hash of\nthe expected content.  When the attacker provides some other\nGPG-encrypted content, it will fail the hash check and be discarded.\n",
  "id": "HSEC-2023-0011",
  "modified": "2025-11-14T14:45:34Z",
  "published": "2025-11-14T14:45:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://git-annex.branchable.com/security/CVE-2018-10857_and_CVE-2018-10859/"
    }
  ],
  "related": [
    "HSEC-2023-0010",
    "CVE-2018-10857"
  ],
  "schema_version": "1.5.0",
  "summary": "git-annex GPG decryption attack via compromised remote"
}

CVE-2018-10859 (GCVE-0-2018-10859)

Vulnerability from cvelistv5 – Published: 2018-07-16 18:00 – Updated: 2024-08-05 07:46

Summary

git-annex is vulnerable to an Information Exposure when decrypting files. A malicious server for a special remote could trick git-annex into decrypting a file that was encrypted to the user's gpg key. This attack could be used to expose encrypted data that was never stored in git-annex

Severity ?

5.9 (Medium)


                        
                          CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE

CWE-200

Assigner

redhat

References

URL

	Vendor	Product	Version
	[UNKNOWN]	git-annex	Affected: n/a

CVE-2018-10857 (GCVE-0-2018-10857)

Vulnerability from cvelistv5 – Published: 2018-07-16 20:00 – Updated: 2024-08-05 07:46

Summary

git-annex is vulnerable to a private data exposure and exfiltration attack. It could expose the content of files located outside the git-annex repository, or content from a private web server on localhost or the LAN.

Severity ?

5.9 (Medium)


                        
                          CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

CWE

CWE-200

Assigner

redhat

References

URL

	Vendor	Product	Version
	[UNKNOWN]	git-annex	Affected: n/a

hsec-2023-0011

Vulnerability from osv_haskell

Published

2025-11-14 14:45

Modified

2025-11-14 14:45

Summary

git-annex private data exfiltration to compromised remote

Details

git-annex private data exfiltration to compromised remote

Some uses of git-annex were vulnerable to a private data exposure and exfiltration attack. It could expose the content of files located outside the git-annex repository, or content from a private web server on localhost or the LAN. Joey Hess discovered this attack.

To perform this attack, the attacker needs to have control over one of the remotes of the victim's git-annex repository. For example, they may provide a public git-annex repository that the victim clones. Or, equivalantly, the attacker could have read access to the victim's git-annex repository or a repository it pushes to, and some channel to get commits into it (e.g. pull requests).

These exploits are most likely to succeed when the victim is running the git-annex assistant, or is periodically running git annex sync --content.

To perform the attack the attacker runs git-annex addurl --relaxed file:///etc/passwd and commits this to the repository in some out of the way place. After the victim's git repository receives that change, git-annex follows the attacker-provided URL to the private data, which it stores in the git-annex repository. From there it transfers the content to the remote git-annex repository that the attacker has access to.

As well as file:/// URLs, the attacker can use URLs to private web servers. The URL can also be one that the attacker controls, that redirects to a URL that is accessible to the victim system (and not necessarily the compromised remote).

Fix

The issue was fixed by making git-annex refuse to follow file:/// urls and URLs pointing to private/local IP addresses by default. Two new configuration settings, annex.security.allowed-url-schemes and annex.security.allowed-ip-addresses, can relax this security policy, and are intended for cases where the git-annex repository is kept private and so the attack does not apply.

Impact on external special remotes

One variant of this issue can exploit a vulnerable external special remote, and could not be prevented by git-annex. (git-annex's own built-in special remotes are not vulnerable to this attack.)

In this attack variant, the attacker guesses the hash of a file stored on the victim's private web server, and adds it to the git-annex repository. The attacker also has control of the server hosting an encrypted special remote used by the victim's git-annex repository. They cause that server to redirect to the victim's web server. This allows the attacker to verify if the victim's web server contains a file that the attacker already knows the content of, assuming they can guess the URL to it.

Developers of external special remotes are encouraged to prevent this attack by not following such HTTP redirects.

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "human_link": "https://github.com/haskell/security-advisories/tree/main/advisories/published/2023/HSEC-2023-0010.md",
        "osv": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export/2023/HSEC-2023-0010.json"
      },
      "package": {
        "ecosystem": "Hackage",
        "name": "git-annex"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.20180626"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "severity": [
        {
          "score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N",
          "type": "CVSS_V3"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2018-10857"
  ],
  "database_specific": {
    "home": "https://github.com/haskell/security-advisories",
    "osvs": "https://raw.githubusercontent.com/haskell/security-advisories/refs/heads/generated/osv-export",
    "repository": "https://github.com/haskell/security-advisories"
  },
  "details": "# *git-annex* private data exfiltration to compromised remote\n\nSome uses of git-annex were vulnerable to a private data exposure\nand exfiltration attack. It could expose the content of files\nlocated outside the *git-annex* repository, or content from a\nprivate web server on localhost or the LAN.  Joey Hess discovered\nthis attack.\n\nTo perform this attack, the attacker needs to have control over one\nof the remotes of the victim\u0027s *git-annex* repository. For example,\nthey may provide a public *git-annex* repository that the victim\nclones. Or, equivalantly, the attacker could have read access to the\nvictim\u0027s *git-annex* repository or a repository it pushes to, and\nsome channel to get commits into it (e.g. pull requests).\n\nThese exploits are most likely to succeed when the victim is running\nthe `git-annex` assistant, or is periodically running `git annex\nsync --content`.\n\nTo perform the attack the attacker runs `git-annex addurl --relaxed\nfile:///etc/passwd` and commits this to the repository in some out\nof the way place.  After the victim\u0027s git repository receives that\nchange, `git-annex` follows the attacker-provided URL to the private\ndata, which it stores in the *git-annex* repository.  From there it\ntransfers the content to the remote *git-annex* repository that the\nattacker has access to.\n\nAs well as `file:///` URLs, the attacker can use URLs to private web\nservers.  The URL can also be one that the attacker controls, that\nredirects to a URL that is accessible to the victim system (and not\nnecessarily the compromised remote).\n\n## Fix\n\nThe issue was fixed by making `git-annex` refuse to follow\n`file:///` urls and URLs pointing to private/local IP addresses by\ndefault.  Two new configuration settings,\n`annex.security.allowed-url-schemes` and\n`annex.security.allowed-ip-addresses`, can relax this security\npolicy, and are intended for cases where the *git-annex* repository\nis kept private and so the attack does not apply.\n\n## Impact on external special remotes\n\nOne variant of this issue can exploit a vulnerable external special\nremote, and could not be prevented by `git-annex`.  (`git-annex`\u0027s\nown built-in special remotes are not vulnerable to this attack.)\n\nIn this attack variant, the attacker guesses the hash of a file\nstored on the victim\u0027s private web server, and adds it to the\n`git-annex` repository.  The attacker also has control of the server\nhosting an encrypted special remote used by the victim\u0027s *git-annex*\nrepository.  They cause that server to redirect to the victim\u0027s web\nserver.  This allows the attacker to verify if the victim\u0027s web\nserver contains a file that the attacker already knows the content\nof, assuming they can guess the URL to it.\n\nDevelopers of external special remotes are encouraged to prevent\nthis attack by not following such HTTP redirects.\n",
  "id": "HSEC-2023-0010",
  "modified": "2025-11-14T14:45:34Z",
  "published": "2025-11-14T14:45:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://git-annex.branchable.com/security/CVE-2018-10857_and_CVE-2018-10859/"
    }
  ],
  "schema_version": "1.5.0",
  "summary": "git-annex private data exfiltration to compromised remote"
}

Sightings

Author	Source	Type	Date

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.

Detection rules are retrieved from Rulezet.

Action not permitted

hsec-2023-0011

Vulnerability from osv_haskell

git-annex GPG decryption attack via compromised remote

CVE-2018-10859 (GCVE-0-2018-10859)

CVE-2018-10857 (GCVE-0-2018-10857)

hsec-2023-0011

Vulnerability from osv_haskell

git-annex private data exfiltration to compromised remote

Fix

Impact on external special remotes

Tags

Sightings

Nomenclature