What is the yabs-sid cookie?
yabs-sid is an HTTP cookie associated with Yandex's advertising platform ("YABS" – Yandex Advertising/Banner System), part of the Russian search engine and online services company that also runs its own contextual and display advertising network, comparable to Google Ads.
The cookie typically appears when a page loads a Yandex script (for example Yandex.Metrica, a Yandex widget, or an ad served through the Yandex advertising network) and is set on the .yandex.ru domain rather than directly by the site the visitor is browsing. As a session cookie, it expires when the browser is closed.
What data it stores
The cookie stores a session identifier generated by Yandex, used to link successive requests from the same visitor within its advertising system. The exact value format is not documented in detail publicly and may vary; it is not intended to hold directly identifying information such as a name or email address.
Data collected through this cookie is sent to Yandex's servers, where it supports browsing-behavior analysis and real-time ad delivery and optimization.
What it is used for
For Yandex, the cookie helps correlate a visitor's actions during a single browsing session, supporting functions such as ad frequency capping, campaign performance measurement, and audience segmentation.
For a website owner, this cookie is usually a side effect of embedding a Yandex tool (analytics, click-heatmaps, or ads) rather than a deliberate choice about the cookie itself.
Does it require consent?
yabs-sid is classified as a marketing cookie (advertising/tracking) and is not strictly necessary for the site to function. Under the GDPR (Regulation 2016/679) and the ePrivacy Directive (transposed in Romania via Law 506/2004), placing it requires the visitor's prior, informed, and freely given consent.
- Site owners must list this cookie in their cookie policy, including provider, purpose, and duration.
- The Yandex script that generates it should load only after the visitor accepts the "marketing" category in the consent banner.
- Refusing consent must not block access to the site's content.
How to block or delete yabs-sid
A visitor can delete or block this cookie anytime from browser settings (per-site or per-domain cookie controls for yandex.ru), or use an anti-tracking/ad-blocking extension targeting advertising domains.
Site owners cannot control the cookie's content directly since it is set by Yandex, but they can control when the Yandex script loads. A consent management platform (CMP) such as CookieFix automatically blocks marketing scripts, including those that would trigger yabs-sid, until the visitor gives explicit consent for that category.
Frequently asked questions
It's a session cookie set by Yandex, used by the company's internal advertising system to identify a visit within its ad network.
It's not malware, but it is a tracking cookie used for advertising purposes, which is why it requires visitor consent under GDPR.
As a session cookie, it is automatically deleted when the browser closes and does not persist across separate visits.
Yes, since it's a marketing cookie, the Yandex script that generates it should stay blocked until the visitor explicitly accepts that category in the cookie banner.