Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc91bca3ca583134…

MALICIOUS

PDF

87.1 KB Created: 2021-06-28 09:52:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: aad35b70a9ab2af2a7bfc126b97c2c6f SHA-1: 535b2466f21b20228f69b875f479bbca74ec2368 SHA-256: dc91bca3ca583134ea64813a486415a15208fb8d6d5dff09c1c6528e6bf826bf
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. The document functions as a link farm, containing numerous URLs that point to external resources, including compromised WordPress upload directories. These links likely serve to redirect users to malicious sites or download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

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
  • 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://krisoc.ru/uplcv?utm_term=motor+vehicle+dynamics+modeling+and+simulation
    • https://ksuskalology.com/images/file/41553120464.pdf
    • http://dianacb.cz/userfiles/file/lakig.pdf
    • http://elenasteele.com/wp-content/plugins/formcraft/file-upload/server/content/files/16072a791ed5ca---58634022435.pdf
    • http://crmrealty360degree.in/userfiles/file/33008037842.pdf
    • https://www.marthatrotts.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1607ce59323b31---42371733553.pdf
    • http://burmeseburmilla-allevamento.com/userfiles/files/wumidavejewifirolew.pdf
    • http://mountcalvary76.com/clients/9/90/9062e1c9f2360b2cedac6e2854879500/File/78214334260.pdf
    • http://dabien.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/1609a2b581f52d---wakasabuv.pdf
    • https://prsnashville.com/wp-content/plugins/super-forms/uploads/php/files/6ec2305a22fc1896db544373e6200cb8/7472808152.pdf
    • http://mgmkt.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160a11570acff6---zirun.pdf
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16082247005575---33337846208.pdf
    • https://ludifrance.fr/userfiles/file/31000056787.pdf
    • http://xn--pr3b03lcdvwu9dpynqkc.com/DATA/file/20210624140527.pdf
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160826d27bb527---53263699863.pdf
    • http://pwmtqatar.net/userfiles/file/33594726137.pdf
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/16074b1872a91c---muzupiwumonaforoxesobib.pdf
    • https://www.ikedatosou.com/wp-content/plugins/formcraft/file-upload/server/content/files/16087bdc3af945---14891744995.pdf
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078a96276701---fokedofixodivoxalopuxov.pdf
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/5325b5fa19279305d9207e315a51cec3/87125334277.pdf
    • https://tamtam.com.ua/wp-content/plugins/super-forms/uploads/php/files/41eb4faf99ce78a36fce5c2b7beb1fb5/lurevuvomomi.pdf
    • http://networkinglikepro.com/ckfinder/userfiles/files/48987608547.pdf
    • http://backupcenters.com/userfiles/file/71700678397.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f000.bin
ff5e9f2367ed5cb2408bc75e287f9c61f669a319f8cdd0b36a25738d580db609
pdf-font-stream PDF embedded font (sfnt) at offset 0xF000 17604 bytes
font_01_sfnt_off00011d8b.bin
85c431f7920fb916efbe0ebe23a6297027f0afaecae74798bb0d3355cb2dbb17
pdf-font-stream PDF embedded font (sfnt) at offset 0x11D8B 11092 bytes
font_02_sfnt_off00013713.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x13713 16792 bytes