CVE-2022-41793

Executive Summary

CVE-2022-41793 is a critical out-of-bounds write vulnerability residing in the CSR (Certificate Signing Request) format title parsing functionality of Open Babel, a widely used open-source cheminformatics toolbox for interconverting chemical file formats. The flaw affects Open Babel version 3.1.1 and the development master commit 530dbfa3. Successful exploitation via a specially crafted malformed file can lead to arbitrary code execution, granting an attacker the same privileges as the application processing the file. Given the high CVSS score of 9.8 and the absence of a confirmed vendor patch, this vulnerability poses a significant risk to environments handling untrusted chemical data files. Organizations using Open Babel in research, drug discovery, or automated processing pipelines should treat this as a critical finding and implement strict file handling controls.

Technical Analysis

The NVD description identifies an out-of-bounds write vulnerability specifically within the "CSR format title functionality" of Open Babel 3.1.1 and the master commit 530dbfa3. The term "CSR" in the context of Open Babel most likely refers to a specific chemical file format supported by the toolkit. The vulnerability mechanism involves improper bounds checking during the parsing of title data embedded within a malformed CSR file.

The core issue is a classic memory corruption flaw: the application writes data (presumably the title string) to a memory buffer without correctly verifying that the destination buffer has sufficient capacity to hold the incoming data. When an attacker crafts a CSR file with an excessively long title field or with title data structured to exploit the parsing logic, the write operation overflows the allocated buffer, corrupting adjacent memory.

Out-of-bounds writes are a highly dangerous class of memory corruption vulnerabilities. The impact of the corrupted memory depends on the adjacent data. If the overflow overwrites function pointers, return addresses, or other critical control-flow data on the stack or heap, an attacker can redirect program execution. The NVD description explicitly states this can lead to "arbitrary code execution," indicating that the overflow is likely exploitable for control-flow hijacking.

The attack surface is the automated processing of untrusted files. Open Babel is commonly used in scripts and pipelines to batch-convert file formats. Any application or web service that accepts file uploads and processes them with the vulnerable version of Open Babel is exposed. The vulnerability is triggered purely by the file content, meaning no special interaction is required beyond delivering the malicious file to the application.

A technical detail from the description that is relevant to exploitation is the structure of the file. The "title functionality" suggests that the overflow occurs when the parser reads and attempts to store a title field from the CSR file. This likely occurs during the parsing state machine when the specific tag or keyword denoting the title is encountered.

Insufficient technical detail is provided in the NVD description to determine the exact buffer location (stack versus heap), the precise function name where the flaw resides, or the complete structure of the malicious file required. However, the vulnerability class (out-of-bounds write leading to arbitrary code execution) is clear and well-understood. Exploitation of such issues typically involves a malformed input file containing a field designed to exceed expected length limits, with additional data structured to overwrite security-critical memory locations (e.g., a saved return address) with a value pointing to attacker-controlled shellcode or ROP (Return-Oriented Programming) chain placed elsewhere in the file.

Exploitation Scenarios

The attack chain for CVE-2022-41793 is inferred from the vulnerability class and the attack vector described in the NVD entry. This CVE has an "AV:N" component in its high CVSS score, indicating the attack vector is network-based, though the specific delivery mechanism is via a malicious file. No public PoC is available; the attack chain is inferred from the vulnerability class.

Step 1: Reconnaissance and Target Identification An attacker first identifies targets running Open Babel 3.1.1 or the specific master commit 530dbfa3. This can be done by scanning for known applications, web services with file upload features that process chemical data (e.g., molecular visualization tools, structure-based search engines), or internal research environments. The attacker may use banners, error messages, or application fingerprints to detect the specific version. Since Open Babel is often a backend library, the attacker may instead target common platforms known to bundle this version (e.g., specific versions of scientific software or online structure-drawing tools).

Step 2: Crafting the Malicious File The attacker crafts a malicious CSR file. Given the "title functionality" mention, the file likely contains a title field of unusual length or structure. The file is designed to trigger an out-of-bounds write when parsed. The malicious data is structured to overwrite critical memory, such as a return address, with a pointer to attacker-controlled payload data embedded within the same file. The file format itself is the weapon; no prior access to the target system is required. The attacker must know the file format and how Open Babel parses the title to ensure the overflow occurs predictably.

Step 3: Delivery and Trigger The malicious file is delivered to the target. This could be via a web upload form, an email attachment processed by an automated system, a shared network drive, or any other method that results in the file being processed by the vulnerable Open Babel version. Once the application parses the file, the insecure title parsing function executes a write operation that overflows the buffer.

Step 4: Post-Exploitation Impact If exploitation is successful, the attacker achieves arbitrary code execution in the context of the application running Open Babel. The immediate impact is full compromise of the vulnerable application instance. From this foothold, the attacker can pursue lateral movement depending on the environment:

• If Open Babel is part of a web service, the attacker may be able to read environment variables, access backend databases, or pivot to internal network resources.
• If it runs in a high-privilege context (e.g., as root or a domain user), the attacker gains privileged access to the host system.
• The attacker could establish persistence by installing backdoors or creating new accounts.

Since this is a memory corruption vulnerability, the reliability of exploitation may vary, and failed attempts could cause a denial-of-service condition. However, the NVD severity score of 9.8 suggests that successful exploitation is considered highly likely.

Impact Assessment

Confidentiality Impact (C): The NVD description confirms the flaw can lead to arbitrary code execution. An attacker achieving this will have complete control over the user context of the application, allowing them to read any data accessible to that user. This includes sensitive chemical research data, proprietary molecular structures, database credentials, and potentially other files on the system.

Integrity Impact (I): Arbitrary code execution allows the attacker to modify or delete any data accessible to the affected user context. This could corrupt research data, alter molecular structures, plant backdoors in the application files, or tamper with other applications running on the same host.

Availability Impact (A): Exploitation attempts may crash the vulnerable process (out-of-bounds writes often corrupt the heap or stack, leading to segmentation faults). Additionally, a successful attacker can intentionally crash the service, perform ransomware-style encryption, or use the compromised host as a launchpad for attacks on other systems, causing denial-of-service to legitimate users.

Scope: The attack scope is the host running the vulnerable Open Babel application. However, in enterprise networks, the pivot potential is significant. The "Authorization Scopes" and "System" are impacted.

Affected Systems: All deployments running Open Babel version 3.1.1 or the master commit 530dbfa3, including web-based chemical drawing tools, batch conversion pipelines in pharmaceutical research, and automated data ingestion systems.

Blast Radius: The most critical risk is to research and development environments handling proprietary chemical data. A breach could expose intellectual property, trade secrets, or unpublished research. The UNPATCHED status significantly increases the urgency of this risk, as there is no vendor fix available to reduce exposure.

Detection Guidance

Sigma Rule

The following Sigma rule detects potential exploitation attempts by monitoring for the execution context of Open Babel with possible abnormal arguments related to a file named with a .csr extension:

title: Potential CVE-2022-41793 Exploitation via Open Babel
id: 3b937a44-3a1d-4f67-9e13-727b1b3e4b01
status: experimental
description: Detects suspicious Open Babel execution with arguments pointing to .csr files which may be crafted to exploit CVE-2022-41793 (out-of-bounds write in CSR format title parsing).
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2022-41793
author: Valtersit Threat Intel
date: 2024/05/20
logsource:
    category: process_creation
    product: windows
    definition: 'Requires that process creation events are logged at a high level.'
detection:
    selection:
        Image|endswith:
            - '\obabel.exe'
            - '\babel.exe'
        CommandLine|contains|all:
            - '.csr'
            - '-i'
            - '-o'
    condition: selection
falsepositives:
    - Legitimate use of Open Babel to convert .csr files.
level: high

YARA Rule

This YARA rule scans for potential malicious payload content within files, looking for patterns of a CSR file with an excessively large title field:

rule CVE_2022_41793_CSR_Malicious_Payload {
    meta:
        author = "Valtersit Threat Intel"
        description = "Detects potential malicious .CSR files crafted to trigger OOB write in Open Babel title parsing (CVE-2022-41793)"
        date = "2024-05-20"
        reference = "https://nvd.nist.gov/vuln/detail/CVE-2022-41793"
        score = 70
    strings:
        $csr_magic = "CSR" ascii wide nocase
        $title_keyword = "title" ascii wide nocase
        $big_string = { 00 41 41 41 41 41 41 } // 0x00 followed by 'AAAAAA' non-printable pattern
        $nop_sled = { 90 90 90 90 90 }
        $shellcode_pattern = { 31 c0 50 68 2f 2f 73 68 68 2f 62 69 6e 89 e3 } // execve("/bin/sh") shellcode
    condition:
        uint32(0) == 0x43535202 and // file starts with "CSR\x02"
        $title_keyword and
        ( #big_string > 10 or $nop_sled or $shellcode_pattern )
}

Suricata IDS Rule

This Suricata rule detects network traffic that delivers a .csr file with an unusually large size, which may be an attempt to craft an overflowing buffer:

alert http any any -> $HOME_NET any (msg:"Potential CVE-2022-41793 CSR File Delivery"; flow:established,to_server; content:"filename="; nocase; content:".csr"; nocase; http.uri; content:"Content-Type"; nocase; http.header_names; pcre:"/^Content-Length:\s*[0-9]{7,}$/mi"; classtype:attempted-user; sid:2024041701; rev:1;)

Elastic Detection

The following EQL rule detects the process spawning of Open Babel with a suspicious command line containing a .csr file and execution flags:

process where event.action == "exec" and
  (
    process.name == "obabel.exe" or process.name == "babel.exe"
  ) and
  process.args in ("-icsr") and
  process.args in ("-o*") and
  process.args in ("*")

Splunk SPL Query

The following Splunk SPL query will search for Open Babel process execution with suspicious arguments:

index=main sourcetype=ProcessRollup2 OR sourcetype=XmlWinEventLog:Security
| where Image LIKE "%obabel.exe" OR Image LIKE "%babel.exe"
| search CommandLine="*.csr*" AND CommandLine="-i*" AND CommandLine="-o*"
| table _time, host, User, Image, CommandLine, ParentImage
| sort -_time

Wazuh OSSEC Rule

Add the following rule to the Wazuh manager configuration to detect Open Babel execution with CSR files:

<group name="pci_dss_10.6.1,">
  <rule id="100210" level="10">
    <if_sid>500</if_sid>
    <match>obabel|babel</match>
    <regex>\.csr</regex>
    <description>Open Babel execution with potential CVE-2022-41793 malicious CSR file</description>
    <group>pci_dss_10.6.1,</group>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 0/4 — UNPATCHED. The vendor has not released a confirmed patch. The master commit 530dbfa3 is referenced as vulnerable, but no commit that fixes the issue has been identified by the tracked sources.

1) Immediate Mitigations:

• Restrict File Processing: Implement strict file type validation and size limits. Only allow processing of .csr files from trusted internal sources. If file name-based filtering is insufficient, verify the content-type header at the application layer.
• Increase Monitoring: Apply the detection rules above to identify any attempts to trigger this vulnerability. Pay close attention to any file conversion jobs involving .csr files.
• Sandboxing: Run Open Babel in a restricted sandbox (e.g., Docker container, seccomp profile, or a Windows restricted token) with minimal privileges. This limits the blast radius of arbitrary code execution to the sandbox environment.
• Disable Service: If the affected version is being used in a public-facing service that does not require .csr file processing, consider disabling that feature entirely until a patch is available.

2) Patch/Upgrade Steps:

• Monitor Vendor Sources: Continuously monitor the Open Babel repository and security advisory channels for a fix. The master branch commit 530dbfa3 has been flagged as vulnerable, which implies the project may be aware of the issue.
• Upgrade When Available: Upgrade to a patched version of Open Babel as soon as the vendor releases a fix that includes a corrected title-parsing routine in the CSR format handler.
• Custom Build (Risky): If internal expertise is available, recompile the master branch with hardening flags such as -fstack-protector-all and -D_FORTIFY_SOURCE=2. Additionally, manually audit and add bounds-checking to the title parsing code, but this is not a complete solution and is not recommended as a replacement for an official patch.

3) Long-Term Hardening:

• Input Validation Framework: For any application that processes files from untrusted sources, implement a robust input validation framework that validates the entire file structure against the expected schema.
• Memory Safety: When possible, consider using memory-safe alternatives or wrappers for Open Babel that can catch such overflows (e.g., using a scripting language binding that conducts memory checks).
• Regular Audits: Include Open Babel and similar cheminformatics libraries in regular security audits and vulnerability scanning processes to ensure they are kept up to date.
• Network Segmentation: Place research environments that process untrusted chemical data in a segregated network zone to limit lateral movement in case of compromise.

References

1. NVD Entry: https://nvd.nist.gov/vuln/detail/CVE-2022-41793 — The primary source for the CVE data used in this report.
2. Open Babel Official Site: https://openbabel.org/ — Official project website for monitoring patches and version releases.
3. Open Babel GitHub Repository: https://github.com/openbabel/openbabel — Monitor for the master commit 530dbfa3 and future security-related commits addressing this CVE.
4. CISA KEV (Not Listed): https://www.cisa.gov/known-exploited-vulnerabilities-catalog — As of the report date, this CVE is NOT listed in the CISA Known Exploited Vulnerabilities catalog.
5. FIRST EPSS: https://www.first.org/epss/ — The EPSS score of 0.00802 places this CVE in the 53.2% percentile, indicating a moderate probability of exploitation in the wild relative to other known CVEs.

Threat Actor Campaigns: No specific threat actor campaigns or active exploits in the wild have been identified for this CVE as of the report date. The PoC/Exploit status is unknown, but this is not an indicator of safety; rather, it reflects a lack of public disclosure.

Report generated for valtersit.com. This report is based on the provided NVD data and should be updated when more information becomes available.