Medium: unbound

Issue Overview:

A flaw was found in unbound. An integer overflow in regional_alloc function may lead to a buffer overflow of the allocated buffer if the size can be controlled by an attacker and can be big enough. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability. (CVE-2019-25032)

A flaw was found in unbound. An integer overflow in the sldns_str2wire_dname_buf_origin function may lead to a buffer overflow. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability. (CVE-2019-25034)

A flaw was found in unbound. An out-of-bounds write in the sldns_bget_token_par function may be abused by a remote attacker. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability. (CVE-2019-25035)

A flaw was found in unbound. A reachable assertion in the synth_cname function can be triggered by sending invalid packets to the server. If asserts are disabled during compilation, this issue might lead to an out-of-bounds write in dname_pkt_copy function. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability. (CVE-2019-25036)

A flaw was found in unbound. A reachable assertion in the dname_pkt_copy function can be triggered by sending invalid packets to the server. The highest threat from this vulnerability is to service availability. (CVE-2019-25037)

A flaw was found in unbound. An integer overflow in dnsc_load_local_data function may lead to a buffer overflow of the allocated buffer if the size can be controlled by an attacker. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability. (CVE-2019-25038)

A flaw was found in unbound. An integer overflow in ub_packed_rrset_key function may lead to a buffer overflow of the allocated buffer if the size can be controlled by an attacker. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability. (CVE-2019-25039)

A flaw was found in unbound. An infinite loop in dname_pkt_copy function could be triggered by a remote attacker. The highest threat from this vulnerability is to service availability. (CVE-2019-25040)

A flaw was found in unbound. A reachable assertion in the dname_pkt_copy function can be triggered through compressed names. The highest threat from this vulnerability is to service availability. (CVE-2019-25041)

A flaw was found in unbound. An out-of-bounds write in the rdata_copy function may be abused by a remote attacker. The highest threat from this vulnerability is to data confidentiality and integrity as well as service availability. (CVE-2019-25042)

NLnet Labs Unbound, up to and including version 1.12.0, and NLnet Labs NSD, up to and including version 4.3.3, contain a local vulnerability that would allow for a local symlink attack. When writing the PID file, Unbound and NSD create the file if it is not there, or open an existing file for writing. In case the file was already present, they would follow symlinks if the file happened to be a symlink instead of a regular file. An additional chown of the file would then take place after it was written, making the user Unbound/NSD is supposed to run as the new owner of the file. If an attacker has local access to the user Unbound/NSD runs as, she could create a symlink in place of the PID file pointing to a file that she would like to erase. If then Unbound/NSD is killed and the PID file is not cleared, upon restarting with root privileges, Unbound/NSD will rewrite any file pointed at by the symlink. This is a local vulnerability that could create a Denial of Service of the system Unbound/NSD is running on. It requires an attacker having access to the limited permission user Unbound/NSD runs as and point through the symlink to a critical file on the system. (CVE-2020-28935)

Affected Packages:

unbound

Note:

This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.

Issue Correction:
Run yum update unbound to update your system.

New Packages:

aarch64:  
    unbound-1.7.3-15.amzn2.0.1.aarch64  
    unbound-devel-1.7.3-15.amzn2.0.1.aarch64  
    unbound-libs-1.7.3-15.amzn2.0.1.aarch64  
    python2-unbound-1.7.3-15.amzn2.0.1.aarch64  
    python3-unbound-1.7.3-15.amzn2.0.1.aarch64  
    unbound-debuginfo-1.7.3-15.amzn2.0.1.aarch64  
  
i686:  
    unbound-1.7.3-15.amzn2.0.1.i686  
    unbound-devel-1.7.3-15.amzn2.0.1.i686  
    unbound-libs-1.7.3-15.amzn2.0.1.i686  
    python2-unbound-1.7.3-15.amzn2.0.1.i686  
    python3-unbound-1.7.3-15.amzn2.0.1.i686  
    unbound-debuginfo-1.7.3-15.amzn2.0.1.i686  
  
src:  
    unbound-1.7.3-15.amzn2.0.1.src  
  
x86_64:  
    unbound-1.7.3-15.amzn2.0.1.x86_64  
    unbound-devel-1.7.3-15.amzn2.0.1.x86_64  
    unbound-libs-1.7.3-15.amzn2.0.1.x86_64  
    python2-unbound-1.7.3-15.amzn2.0.1.x86_64  
    python3-unbound-1.7.3-15.amzn2.0.1.x86_64  
    unbound-debuginfo-1.7.3-15.amzn2.0.1.x86_64  

Additional References

Red Hat: CVE-2019-25032, CVE-2019-25034, CVE-2019-25035, CVE-2019-25036, CVE-2019-25037, CVE-2019-25038, CVE-2019-25039, CVE-2019-25040, CVE-2019-25041, CVE-2019-25042, CVE-2020-28935

Mitre: CVE-2019-25032, CVE-2019-25034, CVE-2019-25035, CVE-2019-25036, CVE-2019-25037, CVE-2019-25038, CVE-2019-25039, CVE-2019-25040, CVE-2019-25041, CVE-2019-25042, CVE-2020-28935