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Vulnerability · Published Apr 15, 2024 · Assigned by mitre

CVE-2024-31497

Medium 5.9

In plain English

A medium-severity security flaw in the putty package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 5.7% (higher than 93% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)5.7%top 6.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC

Official description

In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if there is no further use of vulnerable PuTTY versions. After a key compromise, an adversary may be able to conduct supply-chain attacks on software maintained in Git. A second, independent scenario is that the adversary is an operator of an SSH server to which the victim authenticates (for remote login or file copy), even though this server is not fully trusted by the victim, and the victim uses the same private key for SSH connections to other services operated by other entities. Here, the rogue server operator (who would otherwise have no way to determine the victim's private key) can derive the victim's private key, and then use it for unauthorized access to those other services. If the other services include Git services, then again it may be possible to conduct supply-chain attacks on software maintained in Git. This also affects, for example, FileZilla before 3.67.0, WinSCP before 6.3.3, TortoiseGit before 2.15.0.1, and TortoiseSVN through 1.14.6.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20putty0.81-r0ALPINE-CVE-2024-31497
Alpine:v3.21putty0.81-r0ALPINE-CVE-2024-31497
Alpine:v3.22putty0.81-r0ALPINE-CVE-2024-31497
Alpine:v3.23putty0.81-r0ALPINE-CVE-2024-31497
Alpine:v3.24putty0.81-r0ALPINE-CVE-2024-31497
Debian:12filezillano fix listedDEBIAN-CVE-2024-31497
Debian:13filezilla3.67.0-1DEBIAN-CVE-2024-31497
Debian:14filezilla3.67.0-1DEBIAN-CVE-2024-31497
Debian:12putty0.78-2+deb12u2DEBIAN-CVE-2024-31497
Debian:13putty0.81-1DEBIAN-CVE-2024-31497
Debian:14putty0.81-1DEBIAN-CVE-2024-31497
Ubuntu:22.04:LTSfilezillano fix listedUBUNTU-CVE-2024-31497
Ubuntu:24.04:LTSfilezillano fix listedUBUNTU-CVE-2024-31497
Ubuntu:22.04:LTSputtyno fix listedUBUNTU-CVE-2024-31497

Affected products (as reported)

VendorProductVersions
n/a n/a n/a

Weakness: CWE-338 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

References