# What is CVE-2017-17688? > CVE-2017-17688 is a medium-severity flaw (CVSS 5.9) in Mail from Apple, published on 16 May 2018. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 5.5%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2017-17688 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 44 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** Medium (CVSS 5.9 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 5.5% (latest exploit-likelihood forecast) - **Published:** 16 May 2018 - **Record last updated:** 5 August 2024 - **Main product:** Mail from Apple - **Affected products:** 11 ## What is CVE-2017-17688? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data. ### The official description The OpenPGP specification allows a Cipher Feedback Mode (CFB) malleability-gadget attack that can indirectly lead to plaintext exfiltration, aka EFAIL. NOTE: third parties report that this is a problem in applications that mishandle the Modification Detection Code (MDC) feature or accept an obsolete packet type, not a problem in the OpenPGP specification ### What kind of flaw is it? - Unknown: Unknown ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Hard: conditions must line up - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read data Severity vector: `CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N` ## Is CVE-2017-17688 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 5.5%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 5.5%, 5.5%, 5.5%, 5.5%, 5.5%, 5.5%, 5.5%. ### Timeline - 16 May 2018: Published - 5 August 2024: Record last updated ### How Precursor Intelligence ranks it CVE-2017-17688 scores **44 out of 100 (Medium)**, with the action "Plan remediation". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2017-17688? The published record lists 11 products. - [Mail](https://www.precursorintelligence.com/product/apple/mail) by [Apple](https://www.precursorintelligence.com/vendors/apple) (Application): version not specified - [Airmail](https://www.precursorintelligence.com/product/bloop/airmail) by [Bloop](https://www.precursorintelligence.com/vendors/bloop) (Application): version not specified - [Emclient](https://www.precursorintelligence.com/product/emclient/emclient) by [Emclient](https://www.precursorintelligence.com/vendors/emclient) (Application): version not specified - [Horde Imp](https://www.precursorintelligence.com/product/horde/horde_imp) by [Horde](https://www.precursorintelligence.com/vendors/horde) (Application): version not specified - [Maildroid](https://www.precursorintelligence.com/product/flipdogsolutions/maildroid) by [Flipdogsolutions](https://www.precursorintelligence.com/vendors/flipdogsolutions) (Application): version not specified - [Mailmate](https://www.precursorintelligence.com/product/freron/mailmate) by [Freron](https://www.precursorintelligence.com/vendors/freron) (Application): version not specified - [Outlook](https://www.precursorintelligence.com/product/microsoft/outlook) by [Microsoft](https://www.precursorintelligence.com/vendors/microsoft) (Application): 2007 - [Postbox](https://www.precursorintelligence.com/product/postbox-inc/postbox) by [Postbox-Inc](https://www.precursorintelligence.com/vendors/postbox-inc) (Application): version not specified - [R2mail2](https://www.precursorintelligence.com/product/r2mail2/r2mail2) by [R2mail2](https://www.precursorintelligence.com/vendors/r2mail2) (Application): version not specified - [Thunderbird](https://www.precursorintelligence.com/product/mozilla/thunderbird) by [Mozilla](https://www.precursorintelligence.com/vendors/mozilla) (Application): version not specified - [Webmail](https://www.precursorintelligence.com/product/roundcube/webmail) by [Roundcube](https://www.precursorintelligence.com/vendors/roundcube) (Application): version not specified ## How do I fix CVE-2017-17688? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisory first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [efail.de](https://efail.de) (Exploit, Mitigation, Third-party advisory) - [flaked.sockpuppet.org](http://flaked.sockpuppet.org/2018/05/16/a-unified-timeline.html) (Third-party advisory) - [securityfocus.com](http://www.securityfocus.com/bid/104162) (Third-party advisory, Vulnerability database) - [securitytracker.com](http://www.securitytracker.com/id/1040904) (Third-party advisory, Vulnerability database) - [lists.gnupg.org](https://lists.gnupg.org/pipermail/gnupg-users/2018-May/060334.html) (Third-party advisory) - [news.ycombinator.com](https://news.ycombinator.com/item?id=17066419) (Issue tracking, Third-party advisory) - [protonmail.com](https://protonmail.com/blog/pgp-vulnerability-efail) (Issue tracking, Third-party advisory) - [twitter.com](https://twitter.com/matthew_d_green/status/995996706457243648) (Third-party advisory) - [patreon.com](https://www.patreon.com/posts/cybersecurity-15-18814817) (Issue tracking, Third-party advisory) - [synology.com](https://www.synology.com/support/security/Synology_SA_18_22) (Third-party advisory) ## Questions ### What is CVE-2017-17688? CVE-2017-17688 is a medium-severity flaw in Mail from Apple, published on 16 May 2018. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data. ### How serious is CVE-2017-17688? It scores 5.9 out of 10 on the CVSS severity scale, which is medium. Our risk score for CVE-2017-17688 is 44 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2017-17688 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 5.5%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2017-17688 affect? For Mail from Apple: version not specified. The record lists 11 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2017-17688? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2017-17688 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact