Malicious PDF — malware analysis report

Static analysis result for SHA-256 f85a991c80c5d9e5…

MALICIOUS

PDF

72.3 KB Created: 2021-09-05 02:03:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: d73e3892d697d9f3f922f43b760397e1 SHA-1: 575825559076f00b14c495144bd6663031fe741b SHA-256: f85a991c80c5d9e5e1f76ade7fa5a7ac67baf74327e62e9d7d1b55bf245eab8b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous external URIs and links to compromised CMS uploads, suggesting it's used to redirect users to malicious sites. The PDF structure and link farm heuristics point towards a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9992

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://queure.ru/uplcv?utm_term=manualidades+zacarias+y+elizabeth PDF link annotation
    • http://ultraljud.nu/bild/files/retixeraxefulururobodir.pdfIn PDF document text
    • https://www.infrascale.com/wp-content/plugins/super-forms/uploads/php/files/386add608f4204e695ba8f168afc8905/paxexe.pdfIn PDF document text
    • http://web5gstore.com/Files/files/zoxodu.pdfIn PDF document text
    • http://lavalnerina.it/userfiles/file/65537288144.pdfIn PDF document text
    • http://xn--tnqz8hz5cb8l.com/upload/files/winovobulerifodakopop.pdfIn PDF document text
    • https://keralahappyjourney.com/ckfinder/userfiles/files/jonujiz.pdfIn PDF document text
    • https://nnt52.ru/userfiles/file/17893416625.pdfIn PDF document text
    • http://cathugo-catamarans.de/res/wysiwyg/file/sefaxususizinirabude.pdfIn PDF document text
    • http://vizugy.hu/uploads/files/woxusuvujuvulufevexawazu.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a66dba7b852---66222504296.pdfIn PDF document text
    • http://www.unidacardoso.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ae442d355a3---fawumupogowemedaxana.pdfIn PDF document text
    • http://angelescare.com/userfiles/file/jowametukepepe.pdfIn PDF document text
    • https://realwebguys.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a586497f972---30023353818.pdfIn PDF document text
    • http://savvyais.com/userfiles/file/72914638444.pdfIn PDF document text
    • https://kitapkaplama.com/upload/ckfinder/files/xijudatadilijonazixo.pdfIn PDF document text
    • http://xn--b1ahhafccpgkb2bxo.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/ccfba10716ced975f1346a4c2095ba52/45601071828.pdfIn PDF document text
    • http://aal.tw/uploads/htmlupload/files/39640421318.pdfIn PDF document text
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/90ae0cfea37134a75113714ef4ec6598/40707582887.pdfIn PDF document text
    • https://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610ae3d88f17d---somivejabisogetavokeku.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_off0000b343.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB343 10756 bytes
SHA-256: 476ea946aaa3dc7fda3d7c569a2b4423de40d447f43678e826f35a7b1aa35da2
font_01_sfnt_off0000cbf3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCBF3 18184 bytes
SHA-256: 3c5ee09b39a4c44986dddec9f043e625ef3a8fc3fb0e710f2901afa426913182
font_02_sfnt_off0000fa61.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA61 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1