PT-2026-36987 · Ruby+2 · Net::Imap+2
CVSS v3.1
6.5
Medium
| Vector | AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
Name of the Vulnerable Software and Affected Versions
net-imap (affected versions not specified)
Description
A hostile IMAP server can trigger a computational denial-of-service attack on the client process during authentication using
SCRAM-SHA1 or SCRAM-SHA256. By sending an arbitrarily large PBKDF2 iteration count in the server-first-message, the server forces the client to execute an expensive OpenSSL::KDF.pbkdf2 hmac() call. Since this function is a blocking C extension that holds the Ruby Global VM Lock (a mechanism that ensures only one thread executes Ruby code at a time), it can freeze the entire Ruby VM and block all threads for several minutes, depending on the hardware and OpenSSL version.Recommendations
Upgrade to a patched version of net-imap and call
Net::IMAP#authenticate using a max iterations keyword argument set to a safe value appropriate for the security context.
Avoid using SCRAM-* mechanisms when authenticating to untrusted servers.Exploit
Fix
DoS
Allocation of Resources Without Limits
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Related Identifiers
Affected Products
Linuxmint
Ubuntu
Net::Imap