GHSA-4cm8-xpfv-jv6f: ZeptoClaw Email Sender Spoofing To Bypass Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4cm8-xpfv-jv6f",
  "modified" : "2026-03-12T16:38:22Z",
  "published" : "2026-03-12T16:38:22Z",
  "aliases" : [ ],
  "summary" : "ZeptoClaw: Email Sender Spoofing to bypass Header-Only From Allowlist Validation",
  "details" : "### Summary\nThe email channel authorizes senders based on the parsed `From` header identity only. If upstream email authentication/enforcement is weak (for example, relaxed SPF/DKIM/DMARC handling), an attacker can spoof an allowlisted sender address and have the message treated as trusted input. \n\n### Details\nRelevant code paths:\n\n- `src/channels/email_channel.rs:311` extracts sender identity from parsed message headers:\n  - `let from = parsed.from() ... a.address() ...`\n- `src/channels/email_channel.rs:328` authorizes using that `from` value:\n  - `if !self.is_sender_allowed(&from) { ... }`\n- `src/channels/email_channel.rs:87` onward (`is_sender_allowed`) performs allowlist/domain matching against the same header-derived value.\n- There is no in-channel validation of sender authenticity indicators such as SPF/DKIM/DMARC results before allowlist trust decisions.\n\nResult:\n- Trust decision is based on a potentially spoofable header field unless mailbox/provider-side anti-spoofing controls are strong and enforced.\n\n### PoC\n1. Configure email channel with strict sender allowlist:\n   - `channels.email.enabled = true`\n   - `channels.email.allowed_senders = [\"ceo@example.com\"]`\n   - `channels.email.deny_by_default = true`\n2. Ensure the monitored mailbox accepts or forwards a spoofed message (for testing, use a local SMTP path that does not enforce sender authentication strongly).\n3. Send an email to the monitored inbox with forged header identity:\n\n```bash\npython - <<'PY'\nimport smtplib\nfrom email.message import EmailMessage\n\nmsg = EmailMessage()\nmsg[\"From\"] = \"ceo@example.com\"   # forged trusted sender\nmsg[\"To\"] = \"bot-inbox@example.net\"\nmsg[\"Subject\"] = \"forged control message\"\nmsg.set_content(\"FORGED EMAIL CONTENT\")\n\n# Example test SMTP endpoint\nwith smtplib.SMTP(\"127.0.0.1\", 25) as s:\n    s.send_message(msg)\nPY\n```\n\n4. Wait for IMAP fetch/IDLE processing.\n5. Observe the message is accepted as allowlisted sender `ceo@example.com` and published as inbound channel input.\n\n### Impact\n- Vulnerability type: sender identity spoofing risk due to header-based authorization.\n- Affected deployments: those using email channel allowlists where upstream anti-spoof controls are weak, misconfigured, or bypassed.\n- Security effect:\n  - Spoofed `From` headers may bypass logical sender allowlist.\n  - Malicious content can enter trusted automation/agent flows as if sent by authorized identities.\n- Risk is reduced in environments with strict SPF/DKIM/DMARC enforcement and strong inbound mail hygiene, but not eliminated at application layer.\n\n### Patch Recommendation\nAdd a sender-authentication gate in `src/channels/email_channel.rs` immediately after parsing `from` (`src/channels/email_channel.rs:311`) and before allowlist enforcement (`src/channels/email_channel.rs:328`). The gate should require trusted SPF/DKIM/DMARC evidence with domain alignment (for example, `DMARC=pass`, or aligned SPF/DKIM pass) before `is_sender_allowed` is evaluated. For backward compatibility, add a configurable mode in `EmailConfig` (for example, `sender_verification_mode`), but recommend hardened settings in production: `dmarc_aligned`, exact-address allowlists, and `deny_by_default=true`.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "zeptoclaw"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.7.6"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 0.7.5"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/qhkm/zeptoclaw/security/advisories/GHSA-4cm8-xpfv-jv6f"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/qhkm/zeptoclaw"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/qhkm/zeptoclaw/releases/tag/v0.7.6"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-306", "CWE-345" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-12T16:38:22Z",
    "nvd_published_at" : null
  }
}