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CVE-2021-26333 - Flaw in AMD PSP chipset affects millions of computers

15 点作者 cvs268超过 3 年前

3 条评论

cvs268超过 3 年前
This is <a href="https:&#x2F;&#x2F;cve.mitre.org&#x2F;cgi-bin&#x2F;cvename.cgi?name=CVE-2021-26333" rel="nofollow">https:&#x2F;&#x2F;cve.mitre.org&#x2F;cgi-bin&#x2F;cvename.cgi?name=CVE-2021-2633...</a> originally discovered in April 2021.<p>The issue was this leaking of previously stored data in system memory, due to reusing the system memory without re-initializing it.<p><pre><code> &gt; If the userspace aapplication requests to initialise 1 byte, &gt; the driver will round that up to a full 4096 bytes, and allocate that much memory. &gt; &gt; However, it will only initialise the first byte, leaving the rest in its prior state. &gt; The user can then access the remaining 4095 bytes which have been untouched, &gt; thus gaining access to the contents of uninitialised memory. </code></pre> Apparently patched in the currently available latest drivers starting from<p>- AMD PSP driver 5.17.0.0<p>- AMD Chipset Driver 3.08.17.735<p><a href="https:&#x2F;&#x2F;www.amd.com&#x2F;en&#x2F;corporate&#x2F;product-security&#x2F;bulletin&#x2F;amd-sb-1009" rel="nofollow">https:&#x2F;&#x2F;www.amd.com&#x2F;en&#x2F;corporate&#x2F;product-security&#x2F;bulletin&#x2F;a...</a>
评论 #28727019 未加载
usr1106超过 3 年前
For those who like myself don&#x27;t know what PSP might be, from the article:<p>&gt; In short, it’s a coprocessor that has access to just about every part of the computers to which it’s inside. This makes it a prime target for attacks. Introduced around 2013, it’s also entirely closed source, existing as an unknown black box within modern AMD CPUs, which makes the security-conscious highly wary. Operating at a low-level, entirely outside the purview of the main CPU and operating system, the PSP, like the IME, is often considered a potential backdoor into a machine.
评论 #28727888 未加载
yrro超过 3 年前
God I HATE this beneath-the-bottom-of-the-barrel quality enterprise value add shite. And the enterprises that keep paying for them without any idea of just how bad the quality is...<p>That said...<p>Don&#x27;t you have to turn the PSP on (like IME) for it to be vulnerable to exploitation?<p>&gt; The first part of the problem is when a user makes a call to the AMD driver to allocate some uninitialised memory using the AMD PSP<p>&gt; The second problem involves calls to the driver to free up contiguous memory space that has previously been allocated.<p>Surely (LOL) unprivileged code isn&#x27;t allowed to make these calls?