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1. Logging to the Danger Zone: Race Condition Attacks and Defenses on System Audit Frameworks

   https://doi.org/10.1145/3372297.3417862  

   Paccagnella, Riccardo; Liao, Kevin; Tian, Dave; Bates, Adam (October 2020, ACM Conference on Computer and Communications Security)

   null (Ed.)

   For system logs to aid in security investigations, they must be beyond the reach of the adversary. Unfortunately, attackers that have escalated privilege on a host are typically able to delete and modify log events at will. In response to this threat, a variety of secure logging systems have appeared over the years that attempt to provide tamper-resistance (e.g., write once read many drives, remote storage servers) or tamper-evidence (e.g., cryptographic proofs) for system logs. These solutions expose an interface through which events are committed to a secure log, at which point they enjoy protection from future tampering. However, all proposals to date have relied on the assumption that an event's occurrence is concomitant with its commitment to the secured log. In this work, we challenge this assumption by presenting and validating a race condition attack on the integrity of audit frameworks. Our attack exploits the intrinsically asynchronous nature of I/O and IPC activity, demonstrating that an attacker can snatch events about their intrusion out of message buffers after they have occurred but before they are committed to the log, thus bypassing existing protections. We present a first step towards defending against our attack by introducing KennyLoggings, the first kernel- based tamper-evident logging system that satisfies the synchronous integrity property, meaning that it guarantees tamper-evidence of events upon their occurrence. We implement KennyLoggings on top of the Linux kernel and show that it imposes between 8% and 11% overhead on log-intensive application workloads. 

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2. Compact and Resilient Cryptographic Tools for Digital Forensics

   https://doi.org/10.1109/CNS48642.2020.9162236  

   Seyitoglu, Efe U.; Yavuz, Attila A.; Ozmen, Muslum Ozgur (June 2020, IEEE Conference on Communications and Network Security (CNS))

   null (Ed.)

   Audit logs play a crucial role in the security of computer systems and are targeted by the attackers due to their forensic value. Digital signatures are essential tools to ensure the authentication/integrity of logs with public verifiability and nonrepudiation. Especially, forward-secure and aggregate signatures (FAS) offer compromise-resiliency and append-only features such that an active attacker compromising a computer cannot tamper or selectively delete the logs collected before the breach. Despite their high-security, existing FAS schemes can only sign a small pre-defined number (K) of logs, and their key-size/computation overhead grows linearly with K. These limitations prevent a practical adoption of FAS schemes for digital forensics. In this paper, we created new signatures named COmpact and REsilient (CORE) schemes, which are (to the best of our knowledge) the first FAS that can sign (practically) unbounded number of messages with only a sub-linear growth in the keysize/computation overhead. Central to CORE is the creation of a novel K-time signature COREKBase that has a small-constant key generation overhead and public key size. We then develop CORE-MMM that harnesses COREK Base via forward-secure transformations. We showed that CORE-MMM significantly outperforms its alternatives for essential metrics. For instance, CORE-MMM provides more than two and one magnitudes faster key updates and smaller signatures, respectively, with smaller private keys. CORE-MMM also offers extra efficiency when the same messages are signed with evolving keys. We formally prove that CORE schemes are secure. Our analysis indicates that CORE schemes are ideal tools to enhance the trustworthiness of digital forensic applications. 

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3. Database memory forensics: Identifying cache patterns for log verification

   https://doi.org/10.1016/j.fsidi.2023.301567  

   Wagner, James; Nissan, Mahfuzul I.; Rasin, Alexander (July 2023, Forensic Science International: Digital Investigation)

   Cyberattacks continue to evolve and adapt to state-of-the-art security mechanisms. Therefore, it is critical for security experts to routinely inspect audit logs to detect complex security breaches. However, if a system was compromised during a cyberattack, the validity of the audit logs themselves cannot necessarily be trusted. Specifically, for a database management system (DBMS), an attacker with elevated privileges may temporarily disable the audit logs, bypassing logging altogether along with any tamper-proof logging mechanisms. Thus, security experts need techniques to validate logs independent of a potentially compromised system to detect security breaches. This paper demonstrates that SQL query operations produce a repeatable set of patterns within DBMS process memory. Operations such as full table scans, index accesses, or joins each produce their own set of distinct forensic artifacts in memory. Given these known patterns, we propose that collecting forensic artifacts from a trusted memory snapshot allows one to reverse-engineer query activity and validate audit logs independent of the DBMS itself and outside the scope of a database administrator's privileges. We rely on the fact the queries must ultimately be processed in memory regardless of any security mechanisms they may have bypassed. This work is generalized to all relational DBMSes by using two representative DBMSes, Oracle and MySQL. 

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4. On the Forensic Validity of Approximated Audit Logs

   https://doi.org/10.1145/3427228.3427272  

   Michael, Noor; Mink, Jaron; Liu, Jason; Gaur, Sneha; Hassan, Wajih Ul; Bates, Adam (December 2020, Annual Computer Security Applications Conference)

   null (Ed.)

   Auditing is an increasingly essential tool for the defense of computing systems, but the unwieldy nature of log data imposes significant burdens on administrators and analysts. To address this issue, a variety of techniques have been proposed for approximating the contents of raw audit logs, facilitating efficient storage and analysis. However, the security value of these approximated logs is difficult to measure—relative to the original log, it is unclear if these techniques retain the forensic evidence needed to effectively investigate threats. Unfortunately, prior work has only investigated this issue anecdotally, demonstrating sufficient evidence is retained for specific attack scenarios. In this work, we address this gap in the literature through formalizing metrics for quantifying the forensic validity of an approximated audit log under differing threat models. In addition to providing quantifiable security arguments for prior work, we also identify a novel point in the approximation design space—that log events describing typical (benign) system activity can be aggressively approximated, while events that encode anomalous behavior should be preserved with lossless fidelity. We instantiate this notion of Attack-Preserving forensic validity in LogApprox, a new approximation technique that eliminates the redundancy of voluminous file I/O associated with benign process activities. We evaluate LogApprox alongside a corpus of exemplar approximation techniques from prior work and demonstrate that LogApprox achieves comparable log reduction rates while retaining 100% of attack-identifying log events. Additionally, we utilize this evaluation to illuminate the inherent trade-off between performance and utility within existing approximation techniques. This work thus establishes trustworthy foundations for the design of the next generation of efficient auditing frameworks. 

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5. Don't Yank My Chain: Auditable NF Service Chaining

   Liu, Guyue; Sadok, Hugo; Kohlbrenner, Anne; Parno, Bryan; Sekar, Vyas; Sherry, Justine (April 2021, 18th USENIX Symposium on Networked Systems Design and Implementation (NSDI 21))

   null (Ed.)

   Auditing is a crucial component of network security practices in organizations with sensitive information such as banks and hospitals. Unfortunately, network function virtualization(NFV) is viewed as incompatible with auditing practices which verify that security functions operate correctly. In this paper, we bring the benefits of NFV to security sensitive environments with the design and implementation of AuditBox. AuditBox not only makes NFV compatible with auditing, but also provides stronger guarantees than traditional auditing procedures. In traditional auditing, administrators test the system for correctness on a schedule, e.g., once per month. In contrast, AuditBox continuously self-monitors for correct behavior, proving runtime guarantees that the system remains in compliance with policy goals. Furthermore, AuditBox remains compatible with traditional auditing practices by providing sampled logs which still allow auditors to inspect system behavior manually. AuditBox achieves its goals by combining trusted execution environments with a lightweight verified routing protocol (VRP). Despite the complexity of service function chain routing policies relative to traditional routing, AuditBox's protocol introduces 72-80% fewer bytes of overhead per packet (in a 5-hop service chain) and provides at 61-67% higher goodput than prior work on VRPs designed for the Internet 

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