Putty
CVE-2013-4206
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, buffer size validation
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 6.8 (MEDIUM). Attack characteristics: network attack vector, M complexity. EPSS exploitation probability: 1.14%. |
| Exploit ScenarioDerived | A remote attacker could corrupt memory to execute arbitrary code or crash the application by sending crafted requests to the affected application. |
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Alert meAnalysisAI
Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code. Rated medium severity (CVSS 6.8), this vulnerability is remotely exploitable. This Buffer Overflow vulnerability could allow attackers to corrupt memory to execute arbitrary code or crash the application.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Use memory-safe languages or bounds-checking. Enable ASLR, DEP/NX, stack canaries. Use safe string functions.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Buffer Overflow (CWE-119), which allows attackers to corrupt memory to execute arbitrary code or crash the application. Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication. Affected products include: Putty, Simon Tatham Putty. Version information: before 0.63.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:M/Au:N/C:P/I:P/A:P
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionCVE.org
Heap-based buffer underflow in the modmul function in sshbn.c in PuTTY before 0.63 allows remote SSH servers to cause a denial of service (crash) and possibly trigger memory corruption or code execution via a crafted DSA signature, which is not properly handled when performing certain bit-shifting operations during modular multiplication.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)CVE.org
The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remot
Stack-based buffer overflow in the SCP command-line utility in PuTTY before 0.67 and KiTTY 0.66.6.3 and earlier allows r
The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large
Multiple untrusted search path vulnerabilities in Putty beta 0.67 allow local users to execute arbitrary code and conduc
PuTTY before 0.75 on Windows allows remote servers to cause a denial of service (Windows GUI hang) by telling the PuTTY
PuTTY before 0.73 on Windows improperly opens port-forwarding listening sockets, which allows attackers to listen on the
Potential recycling of random numbers used in cryptography exists within PuTTY before 0.71. Rated critical severity (CVS
In PuTTY versions before 0.71 on Unix, a remotely triggerable buffer overflow exists in any kind of server-to-client for
PuTTY through 0.75 proceeds with establishing an SSH session even if it has never sent a substantive authentication resp
In PuTTY versions before 0.71 on Windows, local attackers could hijack the application by putting a malicious help file
PuTTY before 0.73 might allow remote SSH-1 servers to cause a denial of service by accessing freed memory locations via
PuTTY before 0.73 mishandles the "bracketed paste mode" protection mechanism, which may allow a session to be affected b
GitHub PoC
Exploit-DB