Malicious PDF — malware analysis report

Static analysis result for SHA-256 857b9ed1698bcecd…

MALICIOUS

PDF

72.1 KB Created: 2021-09-18 00:22:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 8f0c13c8fc1242a6b880c6d0ab465d75 SHA-1: 99df73d32d9fb5c81f5ab44db640685c9c2b3adc SHA-256: 857b9ed1698bcecd622c0f89c02831164b894372f65f711f2f0dcebeba7f7913
96 Risk Score

Malware Insights

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

The PDF document contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable domains, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious, and the heuristic firings confirm its nature as a link farm on potentially compromised infrastructure. The primary goal appears to be directing users to external, untrusted resources.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

Heuristics 5

  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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://allytemp.ru/uplcv?utm_term=how+to+transfer+data+from+android+to+android+using+usb+cable PDF link annotation
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/b3r6id1m7bt1ltj0eri03ekcrc/xolinoluzaramuretefupawu.pdfIn PDF document text
    • http://ukwoodrecycling.com/userfiles/files/93557916619.pdfIn PDF document text
    • https://www.privathospitaletkollund.com/ckfinder/userfiles/files/xudijeralof.pdfIn PDF document text
    • http://adamex.ukrkarta.ua/fckeditor/userfiles/file/fabodaxora.pdfIn PDF document text
    • http://xn--80aaffebba2apgigwiiececnggk9e4k.xn--p1ai/pict/file/lobufobuwasegigow.pdfIn PDF document text
    • http://technimexvn.com/images/ckeditor/files/guxumoxefupajixijapidejan.pdfIn PDF document text
    • https://tdfstore.it/file/17146412561.pdfIn PDF document text
    • http://21cedu.com/pds/userfiles/files/21139500893.pdfIn PDF document text
    • http://coral-travel66.ru/admin/ckfinder/userfiles/files/41984799256.pdfIn PDF document text
    • http://baliretreatcenter.com/olabali_ci/media/images/newsfiles/tugozapizepu.pdfIn PDF document text
    • https://sporyolu.com/resimler/files/fifumupakepulon.pdfIn PDF document text
    • http://capableapp.com/uploads/files/21445646162.pdfIn PDF document text
    • http://netdepphunu.vn/images/userfiles/file/66298589702.pdfIn PDF document text
    • http://nissanotogovap.vn/uploads/images/files/duvapokot.pdfIn PDF document text
    • http://goldmustang.ru/files/files/73498722687.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161334ed78bde2---60760843815.pdfIn PDF document text
    • http://ballarioarchitetti.eu/userfiles/files/44172482168.pdfIn PDF document text
    • http://malopolskiszlakwinny.pl/upload/File/31911340324.pdfIn PDF document text
    • https://sibiucuratenie.ro/fckeditor/userfiles/file/fivobinifuvikopipi.pdfIn PDF document text
    • http://abbuffalowings.com/uploads/files/fuvumosodilifi.pdfIn PDF document text
    • http://www.argentum.com/wp-content/plugins/super-forms/uploads/php/files/07tug3jp39h284aper20q786k1/37690812363.pdfIn PDF document text
    • http://urgentcarepb.com/userfiles/file/75860572890.pdfIn PDF document text
    • http://bjdfszwy.com/filespath/files/20210917081054.pdfIn PDF document text
    • http://xn--80aafbladvtgxneccoge3bt.xn--p1ai/pict/file/95775707561.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_off0000b637.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB637 16468 bytes
SHA-256: 14a036655b8160f09c2784a68ae9cd1f668e8e2c135bf3d40d341adb5636595c
font_01_sfnt_off0000e002.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE002 11136 bytes
SHA-256: 08967c63f0ec2655bba901663587d0c94fdc6b1594207d0df12614ebcf5a361d
font_02_sfnt_off0000f9d1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF9D1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1