Malicious PDF — malware analysis report

Static analysis result for SHA-256 c5651d83694581f1…

MALICIOUS

PDF

83.0 KB Created: 2021-09-10 23:55:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: a23fb9fe20d3643dfd5e7a36e90dd20f SHA-1: 52ec71e6712bdca54cee10238cfa22c1f6ca061d SHA-256: c5651d83694581f1208da8aae2eaefd8908161bd0654c5733b5cd4bfacacb1ef
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ClamAV as a phishing trojan and by an ML classifier as malicious. It contains embedded JavaScript and numerous external URIs, many of which point to disposable domains and appear to be part of a link farm. The embedded JavaScript likely facilitates the redirection to these external sites, which are probably used to host further malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://whkmradio.com/userfiles/file/zomofitoraxom.pdf In PDF document text
    • http://chhattisgarhsanskritboard.in/sharpinstitute/images/files/virefar.pdfIn PDF document text
    • http://bjjiffy.com/upload/nabiguweduzipoj.pdfIn PDF document text
    • http://poliinc.com/upload/files/deporuvagemekig.pdfIn PDF document text
    • http://artanuji.ge/admin/ckeditor/ckfinder/userfiles/files/61781286489.pdfIn PDF document text
    • http://veraschwemmle.de/fckdata/file/30770826592.pdfIn PDF document text
    • http://siciny.eu/userfiles/file/28004636469.pdfIn PDF document text
    • http://thestarbusan.com/FileData/ckfinder/files/20210901_912186BDDE2FCD26.pdfIn PDF document text
    • https://skinrepublic.vn/webroot/img/files/lezapove.pdfIn PDF document text
    • http://www.siscard.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136449255c72---nijosomunajaxofijolenojuf.pdfIn PDF document text
    • http://hokkaido-love87.com/app/webroot/js/ckfinder/userfiles/files/nupofi.pdfIn PDF document text
    • http://barbusci.it/maisUserFile/file/bogazunekuvazozumepalavuk.pdfIn PDF document text
    • http://www.oomedia.com.tw/ckfinder/userfiles/files/susurebalexinugag.pdfIn PDF document text
    • http://dulichtantai.com/files/uploaded/files/rokunekiboled.pdfIn PDF document text
    • https://chulintemple.house-well.com/CKEdit/upload/files/51215049311.pdfIn PDF document text
    • http://quangcaosms.org/media/ftp/file/lugowaxumi.pdfIn PDF document text
    • http://abwcockeysville.com/uploads/files/wererokaluwodu.pdfIn PDF document text
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/a78db01d7b6f174efac97268ca0d58b3/rabetanakiranizowez.pdfIn PDF document text
    • http://xedaptheduc.net/app/webroot/uploads/files/lewex.pdfIn PDF document text
    • http://rustproofingottawa.com/userfiles/file/tupevasibivaxavuzu.pdfIn PDF document text
    • https://copab.tn/216mag.svn/uploads/files/57009089019.pdfIn PDF document text
    • http://veewood.com/file_media/file_image/file/87113883307.pdfIn PDF document text
    • https://al-farh-iq.com/upload/userfiles/file/wilozalazop.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=redmi+note+9+pro+genshin+impact+settingsPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dc66.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC66 18536 bytes
SHA-256: 95f2c1ca7e7d1718e0981de3ae078c260ea530905d9566fc411e755b15ab84a0
font_01_sfnt_off00010ca4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CA4 11128 bytes
SHA-256: 8113cbef23a632f2831a783991b4493b113c19a481183c583f9935f06055f205
font_02_sfnt_off00012645.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12645 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1