CVE-2022-31081
📋 TL;DR
CVE-2022-31081 is an HTTP request smuggling vulnerability in HTTP::Daemon Perl library versions before 6.15. It allows attackers to bypass security controls, poison caches, or gain unauthorized API access by sending malformed Content-Length headers. This primarily affects developers using HTTP::Daemon for local development and testing, though production deployments are rare.
💻 Affected Systems
- HTTP::Daemon Perl library
📦 What is this software?
\ by Http\
⚠️ Risk & Real-World Impact
Worst Case
Privileged API access, cache poisoning leading to credential theft or data manipulation, and potential escalation to backend systems.
Likely Case
Cache poisoning in development environments, potential API abuse in improperly configured deployments.
If Mitigated
Minimal impact with proper request validation or when used behind reverse proxies like Nginx/Apache.
🎯 Exploit Status
Exploitation requires crafting malformed HTTP requests with abnormal Content-Length headers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.15
Vendor Advisory: http://metacpan.org/release/HTTP-Daemon/
Restart Required: Yes
Instructions:
1. Update HTTP::Daemon via CPAN: 'cpan HTTP::Daemon'
2. Verify version >=6.15
3. Restart any services using HTTP::Daemon
🔧 Temporary Workarounds
Request validation workaround
allAdd Content-Length header validation before processing requests
# In Perl code after $conn->get_request():
my $cl = $rqst->header('Content-Length');
if ($cl && $cl !~ /^\d+(?:,\s*\d+)*$/) {
$conn->send_error(400);
return;
}
🧯 If You Can't Patch
- Deploy HTTP::Daemon behind reverse proxy (Nginx/Apache) with proper request validation
- Implement network segmentation to isolate HTTP::Daemon instances from sensitive systems
🔍 How to Verify
Check if Vulnerable:
Check Perl module version: 'perl -MHTTP::Daemon -e "print $HTTP::Daemon::VERSION\n"'Check Version:
perl -MHTTP::Daemon -e "print $HTTP::Daemon::VERSION\n"Verify Fix Applied:
Confirm version is 6.15 or higher using same command📡 Detection & Monitoring
Log Indicators:
- HTTP 400 errors with malformed Content-Length headers
- Unusual request patterns with multiple Content-Length values
Network Indicators:
- HTTP requests with non-numeric or multiple Content-Length headers
- Requests that bypass normal validation
SIEM Query:
http.content_length:*[^0-9,]* OR http.content_length:*,,*🔗 References
- http://metacpan.org/release/HTTP-Daemon/
- https://cwe.mitre.org/data/definitions/444.html
- https://datatracker.ietf.org/doc/html/rfc7230#section-9.5
- https://github.com/libwww-perl/HTTP-Daemon/commit/8dc5269d59e2d5d9eb1647d82c449ccd880f7fd0
- https://github.com/libwww-perl/HTTP-Daemon/commit/e84475de51d6fd7b29354a997413472a99db70b2
- https://github.com/libwww-perl/HTTP-Daemon/security/advisories/GHSA-cg8c-pxmv-w7cf
- https://lists.debian.org/debian-lts-announce/2022/09/msg00038.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7U4XEPZ5Q3LNOQF3E6EXFWVSEXU5IZ6T/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ECJ4ZPBQWD3B2CD6RRIVMENB5KUOJ3LC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XQBW2D43TDNYX4R2YBTNNZDBNZ45DINN/
- https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn
- http://metacpan.org/release/HTTP-Daemon/
- https://cwe.mitre.org/data/definitions/444.html
- https://datatracker.ietf.org/doc/html/rfc7230#section-9.5
- https://github.com/libwww-perl/HTTP-Daemon/commit/8dc5269d59e2d5d9eb1647d82c449ccd880f7fd0
- https://github.com/libwww-perl/HTTP-Daemon/commit/e84475de51d6fd7b29354a997413472a99db70b2
- https://github.com/libwww-perl/HTTP-Daemon/security/advisories/GHSA-cg8c-pxmv-w7cf
- https://lists.debian.org/debian-lts-announce/2022/09/msg00038.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7U4XEPZ5Q3LNOQF3E6EXFWVSEXU5IZ6T/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ECJ4ZPBQWD3B2CD6RRIVMENB5KUOJ3LC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XQBW2D43TDNYX4R2YBTNNZDBNZ45DINN/
- https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn
