CVE-2022-31081 (published 2022-06-27T21:15Z)

HTTP::Daemon is a simple http server class written in perl. Versions prior to 6.15 are subject to a vulnerability which could potentially be exploited to gain privileged access to APIs or poison intermediate caches. It is uncertain how large the risks are, most Perl based applications are served on top of Nginx or Apache, not on the `HTTP::Daemon`. This library is commonly used for local development and tests. Users are advised to update to resolve this issue. Users unable to upgrade may add additional request handling logic as a mitigation. After calling `my $rqst = $conn->get_request()` one could inspect the returned `HTTP::Request` object. Querying the 'Content-Length' (`my $cl = $rqst->header('Content-Length')`) will show any abnormalities that should be dealt with by a `400` response. Expected strings of 'Content-Length' SHOULD consist of either a single non-negative integer, or, a comma separated repetition of that number. (that is `42` or `42, 42, 42`). Anything else MUST be rejected.

Severity: MEDIUM
CVSS v2 base score: 6.4 (AV:N/AC:L/Au:N/C:P/I:P/A:N)
CVSS v3 base score: 6.5, MEDIUM (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)

Weakness information:
cwe_id: CWE-444
cwe_name: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
description: The product acts as an intermediary HTTP agent
         (such as a proxy or firewall) in the data flow between two
         entities such as a client and server, but it does not
         interpret malformed HTTP requests or responses in ways that
         are consistent with how the messages will be processed by
         those entities that are at the ultimate destination.
extended_description: 
	   HTTP requests or responses ("messages") can be
	   malformed or unexpected in ways that cause web servers or
	   clients to interpret the messages in different ways than
	   intermediary HTTP agents such as load balancers, reverse
	   proxies, web caching proxies, application firewalls,
	   etc. For example, an adversary may be able to add duplicate
	   or different header fields that a client or server might
	   interpret as one set of messages, whereas the intermediary
	   might interpret the same sequence of bytes as a different
	   set of messages. For example, discrepancies can arise in
	   how to handle duplicate headers like two Transfer-encoding
	   (TE) or two Content-length (CL), or the malicious HTTP
	   message will have different headers for TE and
	   CL.
	   The inconsistent parsing and interpretation of messages
	   can allow the adversary to "smuggle" a message to the
	   client/server without the intermediary being aware of it.
	   This weakness is usually the result of the usage
	   of outdated or incompatible HTTP protocol versions in the
	   HTTP agents.
         
         

Fix information:
repo_url: https://github.com/libwww-perl/HTTP-Daemon
commit_details: repo_url: https://github.com/libwww-perl/HTTP-Daemon
author: Theo van Hoesel
author_date: 2022-06-16 08:28:30+00:00
msg: Fix Content-Length ', '-separated string issues

After a security issue, we ensure we comply to
RFC-7230 -- HTTP/1.1 Message Syntax and Routing
- section 3.3.2 -- Content-Length
- section 3.3.3 -- Message Body Length
repository: repo_url: https://github.com/libwww-perl/HTTP-Daemon
repo_name: libwww-perl/HTTP-Daemon
description: A simple http server class
repo_language: Perl
owner: libwww-perl
file_changes: filename: Daemon.pm
change_type: ModificationType.MODIFY
diff: @@ -288,6 +288,32 @@ READ_HEADER:
     }
     elsif ($ct_len) {
 
+        # After a security issue, we ensure we comply to
+        # RFC-7230 -- HTTP/1.1 Message Syntax and Routing
+        # section 3.3.2 -- Content-Length
+        # section 3.3.3 -- Message Body Length
+
+        # split and clean up Content-Length ', ' separated string
+        my @vals = map {my $str = $_; $str =~ s/^\s+//; $str =~ s/\s+$//; $str }
+            split ',', $ct_len;
+        # check that they are all numbers (RFC: Content-Length = 1*DIGIT)
+        my @nums = grep { /^[0-9]+$/} @vals;
+        unless (@vals == @nums) {
+            $self->send_error(400);
+            $self->reason("Content-Length value must be a unsigned integer");
+            return;
+        }
+        # check they are all the same
+        my $ct_len = shift @nums;
+        foreach (@nums) {
+            next if $_ == $ct_len;
+            $self->send_error(400);
+            $self->reason("Content-Length values are not the same");
+            return;
+        }
+        # ensure we have now a fixed header, with only 1 value
+        $r->header('Content-Length' => $ct_len);
+
         # Plain body specified by "Content-Length"
         my $missing = $ct_len - length($buf);
         while ($missing > 0) {

programming_language: Perl
repo_url: https://github.com/libwww-perl/HTTP-Daemon
commit_details: repo_url: https://github.com/libwww-perl/HTTP-Daemon
author: Theo van Hoesel
author_date: 2022-06-21 20:00:47+00:00
msg: Include reason in response body content
repository: repo_url: https://github.com/libwww-perl/HTTP-Daemon
repo_name: libwww-perl/HTTP-Daemon
description: A simple http server class
repo_language: Perl
owner: libwww-perl
file_changes: filename: Daemon.pm
change_type: ModificationType.MODIFY
diff: @@ -299,16 +299,18 @@ READ_HEADER:
         # check that they are all numbers (RFC: Content-Length = 1*DIGIT)
         my @nums = grep { /^[0-9]+$/} @vals;
         unless (@vals == @nums) {
-            $self->send_error(400);
-            $self->reason("Content-Length value must be a unsigned integer");
+            my $reason = "Content-Length value must be an unsigned integer";
+            $self->send_error(400, $reason);
+            $self->reason($reason);
             return;
         }
         # check they are all the same
         my $ct_len = shift @nums;
         foreach (@nums) {
             next if $_ == $ct_len;
-            $self->send_error(400);
-            $self->reason("Content-Length values are not the same");
+            my $reason = "Content-Length values are not the same";
+            $self->send_error(400, $reason);
+            $self->reason($reason);
             return;
         }
         # ensure we have now a fixed header, with only 1 value

programming_language: Perl