CVE-2014-3931
Multi-Router Looking Glass (MRLG) Buffer Overflow Vulnerability
Description
CVE-2014-3931 is a critical memory corruption vulnerability in Multi-Router Looking Glass (MRLG), an open-source network diagnostic tool used by Internet Service Providers (ISPs) and network operators to provide public or internal route server query interfaces. The vulnerability exists in the fastping.c component, where insufficient input validation allows a remote attacker to trigger an arbitrary memory write, leading to memory corruption and potential remote code execution. With a CVSS v3.1 score of 9.8, the flaw requires no authentication, no user interaction, and is exploitable over the network. CISA has added CVE-2014-3931 to the Known Exploited Vulnerabilities catalog, and its EPSS score of 35.56% at the 97th percentile indicates significant exploitation probability.
KEV Information
CVSS Score
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HOpen in CalculatorAffected Products
| Vendor | Product | Version |
|---|---|---|
| multi-router looking glass project | multi-router looking glass | <= 5.4.1 |
Multiple CVSS Assessments
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
References
- http://mrlg.op-sec.us/(Third Party Advisory)
- http://www.s3.eurecom.fr/cve/CVE-2014-3931.txt(Third Party Advisory)
- https://hackerone.com/reports/16330(Exploit, Third Party Advisory)
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2014-3931(US Government Resource)
Weakness Type
CWE-119: Buffer Overflow
CVE-2014-3931 is classified under CWE-119, Improper Restriction of Operations within the Bounds of a Memory Buffer. In MRLG's fastping.c implementation, the application performs operations on a memory buffer without adequately verifying that the read and write operations stay within the buffer's allocated boundaries. This allows a remote attacker to write data to arbitrary memory locations, corrupting program state and potentially redirecting execution flow.
Learn more: CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer
Impact Analysis
CVE-2014-3931 carries maximum impact across all three CIA dimensions. The vulnerability is remotely exploitable (AV:N) with low complexity (AC:L), requires no authentication (PR:N) and no user interaction (UI:N). Confidentiality, integrity, and availability are all rated high (C:H/I:H/A:H) because arbitrary memory write capabilities enable an attacker to read sensitive data from memory, modify program execution flow to gain code execution, and crash the application or underlying system. MRLG instances are typically deployed on network infrastructure servers that have direct access to routing tables, BGP sessions, and network management interfaces, making a compromise particularly dangerous. An attacker who gains code execution on an MRLG server could potentially pivot to network management systems, intercept routing information, or disrupt network operations. The EPSS score of 35.56% at the 97th percentile indicates high exploitation probability, placing this vulnerability in the top 3% of all CVEs.
Exploit Maturity
CVE-2014-3931 has confirmed exploit maturity, with a public exploit report available on HackerOne detailing the memory corruption vector. CISA has confirmed active exploitation by adding CVE-2014-3931 to the KEV catalog. The EPSS score of 35.56% at the 97th percentile indicates significant ongoing exploitation activity. While MRLG is a niche network diagnostic tool, its deployment on ISP infrastructure servers makes it a valuable target for attackers seeking access to network management environments. The vulnerability has been known since 2014, and exploitation is straightforward due to the lack of modern memory protections in the C-based fastping utility. Organizations running MRLG versions 5.4.1 or earlier should assume the tool has been targeted if exposed to untrusted networks.
Remediation
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Upgrade MRLG to version 5.5.0 or later immediately, which addresses the memory corruption vulnerability in fastping.c with proper input validation and bounds checking.
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Restrict network access to the MRLG interface using firewall rules and access control lists. MRLG should only be accessible from trusted management networks and not exposed to the public internet without authentication and rate limiting.
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Deploy MRLG in an isolated network segment separate from critical routing infrastructure. Use network segmentation to prevent lateral movement from a compromised MRLG server to BGP routers, route reflectors, and other network management systems.
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Monitor MRLG server logs and network traffic for signs of exploitation, including abnormal query patterns, unexpected process behavior, crash dumps, and suspicious outbound connections from the MRLG server.
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Consider replacing MRLG with a modern alternative that benefits from memory-safe programming languages and active security maintenance. Evaluate tools written in memory-safe languages (Go, Rust) that provide equivalent looking glass functionality with reduced attack surface.
Technical Details
CVE-2014-3931 is a memory corruption vulnerability in the fastping.c component of Multi-Router Looking Glass (MRLG), with the CVSS v3.1 vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H indicating maximum exploitability and impact. The vulnerability exists in the fastping utility, which is a C-based ICMP ping implementation used by MRLG to perform network reachability checks. Insufficient input validation in the packet processing logic allows a remote attacker to supply crafted input that triggers an out-of-bounds memory write, corrupting adjacent memory regions. Because fastping is written in C without modern memory safety protections (stack canaries, ASLR, or bounds checking), the arbitrary write primitive can be leveraged to overwrite function pointers, return addresses, or other critical data structures to redirect execution flow. The affected versions include all MRLG releases up to and including 5.4.1. The fix in version 5.5.0 implements proper bounds checking on input data and validates buffer sizes before performing memory operations.
Frequently Asked Questions
Is CVE-2014-3931 being actively exploited?
Yes. CISA has added CVE-2014-3931 to the Known Exploited Vulnerabilities catalog, confirming active exploitation. The EPSS score of 35.56% at the 97th percentile indicates the vulnerability is in the top 3% of exploitation probability.
What products are affected by CVE-2014-3931?
Multi-Router Looking Glass (MRLG) versions 5.4.1 and earlier are affected. MRLG is an open-source network diagnostic tool commonly deployed by ISPs and network operators for route server queries and network diagnostics.
How do I fix CVE-2014-3931?
Upgrade MRLG to version 5.5.0 or later. Additionally, restrict network access to the MRLG interface, deploy it in an isolated network segment, and consider replacing it with a modern alternative built with memory-safe programming practices.
How severe is CVE-2014-3931?
With a CVSS score of 9.8 (Critical), CVE-2014-3931 enables unauthenticated remote memory corruption that can lead to arbitrary code execution. Its deployment on ISP infrastructure servers means compromise could impact network routing and management operations.
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