{"id":"GHSA-4cm8-xpfv-jv6f","aliases":[],"status":"published","title":"ZeptoClaw: Email Sender Spoofing to bypass Header-Only From Allowlist Validation","description":"### 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(\u0026from) { ... }`\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 - \u003c\u003c'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":{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium","from":"ghsa"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-306","CWE-345"],"published":"2026-03-12T16:38:22Z","modified":"2026-03-14T04:46:16Z","fixes":[{"ecosystem":"crates.io","package":"zeptoclaw","fixed_in":["0.7.6"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"crates.io","package":"zeptoclaw","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"0.7.5"},{"fixed":"0.7.6"}]}]},{"source":"osv","ecosystem":"crates.io","package":"zeptoclaw","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.7.6"}]}]}],"references":[{"url":"https://github.com/qhkm/zeptoclaw/security/advisories/GHSA-4cm8-xpfv-jv6f","tags":["web"]},{"url":"https://github.com/qhkm/zeptoclaw/releases/tag/v0.7.6","tags":["web"]},{"url":"https://github.com/advisories/GHSA-4cm8-xpfv-jv6f"},{"url":"https://github.com/qhkm/zeptoclaw","tags":["package"]}],"sources":{"ghsa":[{"id":"GHSA-4cm8-xpfv-jv6f","title":"ZeptoClaw: Email Sender Spoofing to bypass Header-Only From Allowlist Validation","description":"### 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(\u0026from) { ... }`\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 - \u003c\u003c'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`.","status":"published","published":"2026-03-12T16:38:22Z","modified":"2026-03-12T16:38:24Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium"}],"cwes":["CWE-306","CWE-345"],"updated_at":"2026-11-02T14:39:35.644357Z"}],"osv":[{"id":"GHSA-4cm8-xpfv-jv6f","title":"ZeptoClaw: Email Sender Spoofing to bypass Header-Only From Allowlist Validation","description":"### 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(\u0026from) { ... }`\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 - \u003c\u003c'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`.","status":"published","published":"2026-03-12T16:38:22Z","modified":"2026-03-14T04:46:16.686765Z","cvss":[{"version":"3.1","score":6.5,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N","level":"medium"}],"cwes":["CWE-306","CWE-345"],"updated_at":"2026-11-02T15:46:36.782754Z"}]}}