Malicious PDF — malware analysis report

Static analysis result for SHA-256 83b05c81f2a8123a…

MALICIOUS

PDF

115.1 KB Created: 2021-09-23 10:46:52 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: a7cb86bbb17f5252e7b73c1e94cc5636 SHA-1: f24312dba71d7b54dbf08f3a7d345261e10161fc SHA-256: 83b05c81f2a8123aabb6ad015cd3cbfb15091a4538a1e0cb899f990aa1ccc190
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF document was flagged by ML classifiers and ClamAV as malicious, specifically identified as a phishing or trojan. It contains numerous embedded URLs, many of which are hosted on disposable domains and appear to be part of a link farm, a common tactic for distributing malware or conducting phishing campaigns. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly indicates this malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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.
  • 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 https://philabc.ru/uplcv?utm_term=resident+evil+6+android+mobile+game PDF link annotation
    • http://reiki-roots.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16136bad65c66d---53473119719.pdfIn PDF document text
    • http://hum-lucknow.org/test/fckeditor/file/68180546085.pdfIn PDF document text
    • https://sintasyapi.com/img/userfiles/file/fimibufidaxirodarimopisu.pdfIn PDF document text
    • http://nanumed.ro/uploads/files/56536032008.pdfIn PDF document text
    • http://jatyn.cn/upfiles/202109/file/1630700444.pdfIn PDF document text
    • https://fpcofmacon.com/nbloom/fckuploads/file/rupaf.pdfIn PDF document text
    • http://azizavacanze.com/userfiles/files/7270180118.pdfIn PDF document text
    • http://tavio.su/files/file/44755899169.pdfIn PDF document text
    • http://aapltd.net/userfiles/file/sojexujulavobivipalot.pdfIn PDF document text
    • http://khojedu.net/userfiles/file/65010779834.pdfIn PDF document text
    • http://focalthai.com/file_media/file_image/file/96601123566.pdfIn PDF document text
    • https://tucsonhomewindowtint.com/wp-content/plugins/super-forms/uploads/php/files/f501cdc16946b68e05166b8ae7a42ff7/nemokipotomobebipovila.pdfIn PDF document text
    • http://ldkxzzs.com/images/userfiles/file/jegupogetopagazasi.pdfIn PDF document text
    • http://www.ctnphrae.com/ckfinder/userfiles/files/kakizogosok.pdfIn PDF document text
    • http://taaltoetsvo.nl/userfiles/file/8322129448.pdfIn PDF document text
    • http://sinostandards.net/upload/files/17516912362.pdfIn PDF document text
    • http://ruihuitax.com/files/file/90069946403.pdfIn PDF document text
    • http://steinbach.casawell.tw/userfiles/file/11781354812.pdfIn PDF document text
    • http://bloemenwinkelindex.nl/images/uploads/63384225400.pdfIn PDF document text
    • http://flightshop.jp/images/blog/file/kunebavekodop.pdfIn PDF document text
    • https://pakistanchristiancongress.pakistanchristianpost.com/userfiles/file/sakosan.pdfIn PDF document text
    • http://megatex-plast.ru/pub/file/xowobofu.pdfIn PDF document text
    • http://yuli-china.ru/d/files/zafudebudasuwojogipefowap.pdfIn PDF document text
    • http://agisinfo.ru/uploads/content/files/1951262439.pdfIn PDF document text
    • http://thermocomfort.ca/userfiles/file/80124866805.pdfIn PDF document text
    • 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_off00015267.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15267 21980 bytes
SHA-256: ff40b1dd1167bacdf382ab41096e6f12c605a7907b1c67f3aa5ac8b2bd023991
font_01_sfnt_off00018c74.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x18C74 11012 bytes
SHA-256: 047a4f3caa57a8f922a1c826adb2732606b247b5ffa27350a23a98db23721206
font_02_sfnt_off0001a5e2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1A5E2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1