CVE-2013-4687 in Junos
Summary
by MITRE
flowd in Juniper Junos 10.4 before 10.4S14, 11.2 and 11.4 before 11.4R6-S2, and 12.1 before 12.1R6 on SRX devices, when certain Application Layer Gateways (ALGs) are enabled, allows remote attackers to cause a denial of service (daemon crash) via crafted TCP packets, aka PRs 727980, 806269, and 835593.
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Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2013-4687 affects the flowd daemon within Juniper Junos operating system versions prior to specific security patches. This issue specifically impacts SRX series devices where certain Application Layer Gateways are enabled, creating a critical weakness in the network device's packet processing capabilities. The vulnerability manifests as a remote denial of service condition that can be triggered by sending carefully crafted TCP packets to the affected system, leading to complete daemon crashes and subsequent service interruption.
The technical flaw resides in the improper handling of TCP packet structures within the flowd daemon when ALG functionality is active. When these application layer gateways are enabled, the system's packet parsing logic fails to properly validate incoming TCP segments, particularly those containing specific sequence numbers or packet headers that trigger buffer overflow conditions or memory corruption within the daemon's processing routines. This weakness falls under CWE-125, which describes out-of-bounds read vulnerabilities, and CWE-129, which covers improper validation of array indices. The vulnerability is particularly dangerous because it operates at the network daemon level, meaning successful exploitation results in complete service disruption rather than merely data compromise.
The operational impact of this vulnerability extends beyond simple service interruption, as it can be exploited remotely without authentication requirements, making it particularly attractive to malicious actors seeking to disrupt network services. Network administrators managing SRX devices with ALG features enabled face significant risk of unauthorized denial of service attacks that could compromise business continuity and network availability. The vulnerability affects multiple Junos versions including 10.4 before 10.4S14, 11.2, 11.4 before 11.4R6-S2, and 12.1 before 12.1R6, indicating a widespread exposure across several major release branches. According to ATT&CK framework, this represents a privilege escalation technique through service disruption, categorized under T1499.004 for Network Denial of Service, and T1566.001 for Phishing via Social Engineering, as attackers might use this vulnerability to create conditions that facilitate further attacks.
Mitigation strategies for CVE-2013-4687 primarily involve applying the appropriate Juniper security patches and updates for the affected Junos versions, which address the underlying packet processing logic flaws in the flowd daemon. Network administrators should also consider disabling ALG functionality on SRX devices when it is not strictly required, as this eliminates the attack surface for this particular vulnerability. Additionally, implementing network segmentation and access controls can help limit the potential impact of successful exploitation attempts, while monitoring for unusual traffic patterns or daemon restarts can provide early detection of attempted attacks. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and conducting regular vulnerability assessments of network infrastructure components, particularly those handling application layer processing functions.