CVE-2025-2516 in WPS Office
Summary
by MITRE • 03/27/2025
The use of a weak cryptographic key pair in the signature verification process in WPS Office (Kingsoft) on Windows allows an attacker who successfully recovered the private key to sign components.
As older versions of WPS Office did not validate the update server's certificate, an Adversary-In-The-Middle attack was possible allowing updates to be hijacked.
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Analysis
by VulDB Data Team • 03/27/2025
The vulnerability identified as CVE-2025-2516 represents a critical weakness in the cryptographic security infrastructure of WPS Office, a widely used office suite developed by Kingsoft. This flaw manifests in the signature verification process where the software employs weak cryptographic key pairs that can be compromised through mathematical attacks or brute force techniques. The vulnerability specifically targets the private key used for digital signatures, creating a pathway for attackers to potentially recover the private key and subsequently forge valid signatures for arbitrary components within the application. The weakness in key generation directly violates fundamental cryptographic principles and compromises the integrity of the software's authentication mechanisms.
The technical implementation of this vulnerability stems from inadequate key strength parameters used during the generation of cryptographic key pairs within the WPS Office signature verification system. According to CWE-326, this represents a weakness in cryptographic key size or generation, where the system fails to implement sufficient entropy or cryptographic strength in key creation. The weak key pairs typically involve insufficient bit lengths or predictable mathematical relationships that make them susceptible to cryptanalytic attacks, including those based on factorization or discrete logarithm problems. Attackers can leverage computational resources and specialized tools to recover these private keys through methods such as Pollard's rho algorithm or other factorization techniques that exploit the mathematical weaknesses inherent in improperly generated keys.
The operational impact of this vulnerability extends beyond simple signature forgery to encompass a broader attack surface that includes man-in-the-middle capabilities. The vulnerability description indicates that older WPS Office versions lacked proper certificate validation of update servers, creating a scenario where attackers could intercept and modify update processes without detection. This represents a classic security architecture flaw that aligns with ATT&CK technique T1036.005, involving the use of valid credentials or certificates to bypass security controls. The combination of weak cryptographic keys and insufficient certificate validation creates a dangerous attack vector where adversaries can not only sign malicious components but also hijack legitimate update processes, potentially leading to arbitrary code execution and complete system compromise. The attack chain typically involves initial compromise through network interception, followed by private key recovery, and culminates in the ability to sign malicious updates that appear legitimate to the victim system.
Mitigation strategies for CVE-2025-2516 require immediate attention and comprehensive remediation across multiple security domains. Organizations should prioritize updating to the latest versions of WPS Office where cryptographic key generation has been strengthened to meet modern security standards, typically requiring at least 2048-bit RSA keys or equivalent elliptic curve cryptography. The implementation of proper certificate validation mechanisms must be enforced to prevent man-in-the-middle attacks, ensuring that all update communications are verified against trusted certificate authorities. Security controls should include network monitoring for suspicious update traffic patterns and implementation of secure update channels that utilize strong cryptographic protocols. From a compliance standpoint, this vulnerability impacts organizations following frameworks such as NIST SP 800-53 and ISO/IEC 27001, where cryptographic key management and certificate validation are critical controls. The remediation process should also include regular security assessments to ensure that cryptographic implementations meet current industry standards and that all components within the software ecosystem maintain proper cryptographic integrity.