[Pkg-clamav-devel] Bug#999662: clamav-daemon: Use systemd isolation features to reduce risk by compromised clamav-daemon
Andreas Feldner
pelzi at feldner-bv.de
Sun Nov 14 12:05:43 GMT 2021
Package: clamav-daemon
Version: 0.103.3+dfsg-0+deb11u1
Severity: wishlist
Dear Maintainer,
clamav-daemon is currently shipped with a systemd unit file that makes
no use of systemd securty features. I found that a number of attack vectors
can be closed without inferring problems with functionality.
This is my version of /lib/systemd/system/clamav-daemon.service that seems to
work OK:
----------------
[Unit]
Description=Clam AntiVirus userspace daemon
Documentation=man:clamd(8) man:clamd.conf(5) https://www.clamav.net/documents/
# Check for database existence
ConditionPathExistsGlob=/var/lib/clamav/main.{c[vl]d,inc}
ConditionPathExistsGlob=/var/lib/clamav/daily.{c[vl]d,inc}
[Service]
ExecStart=/usr/sbin/clamd --foreground=true
User=clamav
# Reload the database
ExecReload=/bin/kill -USR2 $MAINPID
StandardOutput=syslog
TimeoutStartSec=420
PrivateTmp=true
CapabilityBoundingSet=~CAP_SETUID CAP_SETGID CAP_SETPCAP
CapabilityBoundingSet=~CAP_SYS_ADMIN
CapabilityBoundingSet=~CAP_SYS_PTRACE
RestrictNamespaces=~CLONE_NEWUSER
RestrictAddressFamilies=AF_INET AF_INET6 AF_UNIX
CapabilityBoundingSet=~CAP_CHOWN CAP_FSETID CAP_SETFCAP
CapabilityBoundingSet=~CAP_FOWNER CAP_IPC_OWNER
CapabilityBoundingSet=~CAP_NET_ADMIN
CapabilityBoundingSet=~CAP_SYS_MODULE
CapabilityBoundingSet=~CAP_SYS_RAWIO
CapabilityBoundingSet=~CAP_SYS_TIME
[Install]
WantedBy=multi-user.target
----------------
-- Package-specific info:
--- configuration ---
Checking configuration files in /etc/clamav
Config file: clamd.conf
-----------------------
AlertExceedsMax disabled
PreludeEnable disabled
PreludeAnalyzerName = "ClamAV"
LogFile = "/var/log/clamav/clamav.log"
LogFileUnlock disabled
LogFileMaxSize = "4294967295"
LogTime = "yes"
LogClean disabled
LogSyslog disabled
LogFacility = "LOG_LOCAL6"
LogVerbose disabled
LogRotate = "yes"
ExtendedDetectionInfo = "yes"
PidFile disabled
TemporaryDirectory disabled
DatabaseDirectory = "/var/lib/clamav"
OfficialDatabaseOnly disabled
LocalSocket = "/var/run/clamav/clamd.ctl"
LocalSocketGroup = "clamav"
LocalSocketMode = "666"
FixStaleSocket = "yes"
TCPSocket disabled
TCPAddr disabled
MaxConnectionQueueLength = "15"
StreamMaxLength = "26214400"
StreamMinPort = "1024"
StreamMaxPort = "2048"
MaxThreads = "12"
ReadTimeout = "180"
CommandReadTimeout = "30"
SendBufTimeout = "200"
MaxQueue = "100"
IdleTimeout = "30"
ExcludePath disabled
MaxDirectoryRecursion = "15"
FollowDirectorySymlinks disabled
FollowFileSymlinks disabled
CrossFilesystems = "yes"
SelfCheck = "3600"
ConcurrentDatabaseReload = "yes"
DisableCache disabled
VirusEvent disabled
ExitOnOOM disabled
AllowAllMatchScan = "yes"
Foreground disabled
Debug disabled
LeaveTemporaryFiles disabled
User = "clamav"
Bytecode = "yes"
BytecodeSecurity = "TrustSigned"
BytecodeTimeout = "60000"
BytecodeUnsigned disabled
BytecodeMode = "Auto"
DetectPUA disabled
ExcludePUA disabled
IncludePUA disabled
ScanPE = "yes"
ScanELF = "yes"
ScanMail = "yes"
ScanPartialMessages disabled
PhishingSignatures = "yes"
PhishingScanURLs = "yes"
HeuristicAlerts = "yes"
HeuristicScanPrecedence disabled
StructuredDataDetection disabled
StructuredMinCreditCardCount = "3"
StructuredMinSSNCount = "3"
StructuredSSNFormatNormal = "yes"
StructuredSSNFormatStripped disabled
ScanHTML = "yes"
ScanOLE2 = "yes"
AlertBrokenExecutables disabled
AlertBrokenMedia disabled
AlertEncrypted disabled
StructuredCCOnly disabled
AlertEncryptedArchive disabled
AlertEncryptedDoc disabled
AlertOLE2Macros disabled
AlertPhishingSSLMismatch disabled
AlertPhishingCloak disabled
AlertPartitionIntersection disabled
ScanPDF = "yes"
ScanSWF = "yes"
ScanXMLDOCS = "yes"
ScanHWP3 = "yes"
ScanArchive = "yes"
ForceToDisk disabled
MaxScanTime = "120000"
MaxScanSize = "104857600"
MaxFileSize = "26214400"
MaxRecursion = "16"
MaxFiles = "10000"
MaxEmbeddedPE = "10485760"
MaxHTMLNormalize = "10485760"
MaxHTMLNoTags = "2097152"
MaxScriptNormalize = "5242880"
MaxZipTypeRcg = "1048576"
MaxPartitions = "50"
MaxIconsPE = "100"
MaxRecHWP3 = "16"
PCREMatchLimit = "10000"
PCRERecMatchLimit = "5000"
PCREMaxFileSize = "26214400"
OnAccessMountPath disabled
OnAccessIncludePath disabled
OnAccessExcludePath disabled
OnAccessExcludeRootUID disabled
OnAccessExcludeUID disabled
OnAccessExcludeUname disabled
OnAccessMaxFileSize = "5242880"
OnAccessDisableDDD disabled
OnAccessPrevention disabled
OnAccessExtraScanning disabled
OnAccessCurlTimeout = "5000"
OnAccessMaxThreads = "5"
OnAccessRetryAttempts disabled
OnAccessDenyOnError disabled
DevACOnly disabled
DevACDepth disabled
DevPerformance disabled
DevLiblog disabled
DisableCertCheck disabled
AlgorithmicDetection = "yes"
BlockMax disabled
PhishingAlwaysBlockSSLMismatch disabled
PhishingAlwaysBlockCloak disabled
PartitionIntersection disabled
OLE2BlockMacros disabled
ArchiveBlockEncrypted disabled
Config file: freshclam.conf
---------------------------
LogFileMaxSize = "4294967295"
LogTime = "yes"
LogSyslog disabled
LogFacility = "LOG_LOCAL6"
LogVerbose disabled
LogRotate = "yes"
PidFile disabled
DatabaseDirectory = "/var/lib/clamav"
Foreground disabled
Debug disabled
UpdateLogFile = "/var/log/clamav/freshclam.log"
DatabaseOwner = "clamav"
Checks = "24"
DNSDatabaseInfo = "current.cvd.clamav.net"
DatabaseMirror = "db.local.clamav.net", "database.clamav.net"
PrivateMirror disabled
MaxAttempts = "5"
ScriptedUpdates = "yes"
TestDatabases = "yes"
CompressLocalDatabase disabled
ExtraDatabase disabled
ExcludeDatabase disabled
DatabaseCustomURL disabled
HTTPProxyServer disabled
HTTPProxyPort disabled
HTTPProxyUsername disabled
HTTPProxyPassword disabled
HTTPUserAgent disabled
NotifyClamd = "/etc/clamav/clamd.conf"
OnUpdateExecute disabled
OnErrorExecute disabled
OnOutdatedExecute disabled
LocalIPAddress disabled
ConnectTimeout = "30"
ReceiveTimeout disabled
Bytecode = "yes"
clamav-milter.conf not found
Software settings
-----------------
Version: 0.103.3
Optional features supported: MEMPOOL IPv6 FRESHCLAM_DNS_FIX AUTOIT_EA06 BZIP2 LIBXML2 PCRE2 ICONV JSON
Database information
--------------------
Database directory: /var/lib/clamav
bytecode.cld: version 333, sigs: 92, built on Mon Mar 8 16:21:51 2021
main.cld: version 62, sigs: 6647427, built on Thu Sep 16 14:32:42 2021
daily.cld: version 26353, sigs: 1945034, built on Sun Nov 14 10:19:38 2021
Total number of signatures: 8592553
Platform information
--------------------
uname: Linux 5.10.0-8-amd64 #1 SMP Debian 5.10.46-5 (2021-09-23) x86_64
OS: linux-gnu, ARCH: x86_64, CPU: x86_64
Full OS version: Debian GNU/Linux 11 (bullseye)
zlib version: 1.2.11 (1.2.11), compile flags: a9
platform id: 0x0a217c7c08000000000a0201
Build information
-----------------
GNU C: 10.2.1 20210110 (10.2.1)
CPPFLAGS: -Wdate-time -D_FORTIFY_SOURCE=2
CFLAGS: -g -O2 -ffile-prefix-map=/build/clamav-TCDQmt/clamav-0.103.3+dfsg=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64
CXXFLAGS: -g -O2 -ffile-prefix-map=/build/clamav-TCDQmt/clamav-0.103.3+dfsg=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -D_FILE_OFFSET_BITS=64
LDFLAGS: -Wl,-z,relro -Wl,-z,now -Wl,--as-needed
Configure: '--build=x86_64-linux-gnu' '--prefix=/usr' '--includedir=/usr/include' '--mandir=/usr/share/man' '--infodir=/usr/share/info' '--sysconfdir=/etc' '--localstatedir=/var' '--disable-option-checking' '--disable-silent-rules' '--libdir=/usr/lib/x86_64-linux-gnu' '--runstatedir=/run' '--disable-maintainer-mode' '--disable-dependency-tracking' 'CFLAGS=-g -O2 -ffile-prefix-map=/build/clamav-TCDQmt/clamav-0.103.3+dfsg=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -D_FILE_OFFSET_BITS=64' 'CPPFLAGS=-Wdate-time -D_FORTIFY_SOURCE=2' 'CXXFLAGS=-g -O2 -ffile-prefix-map=/build/clamav-TCDQmt/clamav-0.103.3+dfsg=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -D_FILE_OFFSET_BITS=64' 'LDFLAGS=-Wl,-z,relro -Wl,-z,now -Wl,--as-needed' '--with-dbdir=/var/lib/clamav' '--sysconfdir=/etc/clamav' '--disable-clamav' '--disable-unrar' '--enable-milter' '--enable-dns-fix' '--with-libjson' '--with-system-libmspack' '--with-libcurl=/usr' '--with-gnu-ld' '--with-systemdsystemunitdir=/lib/systemd/system' 'build_alias=x86_64-linux-gnu' 'OBJCFLAGS=-g -O2 -ffile-prefix-map=/build/clamav-TCDQmt/clamav-0.103.3+dfsg=. -fstack-protector-strong -Wformat -Werror=format-security'
sizeof(void*) = 8
Engine flevel: 124, dconf: 124
--- data dir ---
total 628240
-rw-r--r-- 1 clamav clamav 1438720 Mar 8 2021 bytecode.cld
-rw-r--r-- 1 clamav clamav 177796096 Nov 14 11:00 daily.cld
-rw-r--r-- 1 clamav clamav 69 Oct 22 13:57 freshclam.dat
-rw-r--r-- 1 clamav clamav 464053248 Sep 16 20:03 main.cld
-rw-r--r-- 1 root root 69 Apr 22 2021 mirrors.dat
drwxr-xr-x 2 clamav clamav 4096 Aug 29 19:04 tmp.c01a6bc443
-- System Information:
Debian Release: 11.1
APT prefers stable-security
APT policy: (500, 'stable-security'), (500, 'stable')
Architecture: amd64 (x86_64)
Kernel: Linux 5.10.0-8-amd64 (SMP w/4 CPU threads)
Kernel taint flags: TAINT_FIRMWARE_WORKAROUND
Locale: LANG=de_DE.UTF-8, LC_CTYPE=de_DE.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
Versions of packages clamav-daemon depends on:
ii adduser 3.118
ii clamav-base 0.103.3+dfsg-0+deb11u1
ii clamav-freshclam [clamav-data] 0.103.3+dfsg-0+deb11u1
ii debconf [debconf-2.0] 1.5.77
ii dpkg 1.20.9
ii libc6 2.31-13+deb11u2
ii libclamav9 0.103.3+dfsg-0+deb11u1
ii libcurl4 7.74.0-1.3+b1
ii libncurses6 6.2+20201114-2
ii libsystemd0 247.3-6
ii libtinfo6 6.2+20201114-2
ii lsb-base 11.1.0
ii procps 2:3.3.17-5
ii ucf 3.0043
ii zlib1g 1:1.2.11.dfsg-2
Versions of packages clamav-daemon recommends:
ii clamdscan 0.103.3+dfsg-0+deb11u1
Versions of packages clamav-daemon suggests:
pn apparmor <none>
pn clamav-docs <none>
pn daemon <none>
pn libclamunrar <none>
-- debconf information:
clamav-daemon/MaxHTMLNormalize: 10M
clamav-daemon/ScanArchive: true
clamav-daemon/LocalSocketMode: 666
clamav-daemon/SelfCheck: 3600
clamav-daemon/StreamMaxLength: 25
clamav-daemon/LogSyslog: false
clamav-daemon/User: clamav
clamav-daemon/MaxConnectionQueueLength: 15
clamav-daemon/ReadTimeout: 180
clamav-daemon/BytecodeTimeout: 60000
clamav-daemon/FollowFileSymlinks: false
clamav-daemon/Bytecode: true
clamav-daemon/MaxDirectoryRecursion: 15
clamav-daemon/FollowDirectorySymlinks: false
clamav-daemon/BytecodeSecurity: TrustSigned
clamav-daemon/LocalSocketGroup: clamav
clamav-daemon/OnAccessMaxFileSize: 5M
clamav-daemon/ScanMail: true
clamav-daemon/FixStaleSocket: true
clamav-daemon/AllowAllMatchScan: true
clamav-daemon/AddGroups: Debian-exim
clamav-daemon/MaxZipTypeRcg: 1M
clamav-daemon/debconf: true
clamav-daemon/MaxScriptNormalize: 5M
clamav-daemon/LocalSocket: /var/run/clamav/clamd.ctl
clamav-daemon/LogRotate: true
clamav-daemon/TCPSocket: 3310
clamav-daemon/ForceToDisk: false
clamav-daemon/TCPAddr: any
clamav-daemon/MaxHTMLNoTags: 2M
clamav-daemon/MaxEmbeddedPE: 10M
clamav-daemon/DisableCertCheck: false
clamav-daemon/ScanSWF: true
clamav-daemon/LogFile: /var/log/clamav/clamav.log
clamav-daemon/LogTime: true
clamav-daemon/MaxThreads: 12
clamav-daemon/TcpOrLocal: UNIX
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