Malicious PDF — malware analysis report

Static analysis result for SHA-256 decdb25654f2bd04…

MALICIOUS

PDF

77.0 KB Created: 2021-03-30 01:41:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-25
MD5: bff162f68c44bb549308c693785b79a8 SHA-1: ced5fe7697d99d7b9f6cf85ee78e134afe342e1a SHA-256: decdb25654f2bd04b0293bf308713fcd474e11ca7e5dfd4cdcec2f930af9f93f
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristics reveal it contains a large number of external links, many pointing to disposable domains, suggesting a link farm or SEO manipulation tactic. The document body, though heavily obfuscated, contains references to 'learning cursive worksheets pdf' and 'wkhtmltopdf', likely serving as a lure to disguise the malicious nature of the embedded links. No scripts were extracted, but the presence of numerous external URLs suggests the primary goal is to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://golowaki.ru/123?utm_term=learning+cursive+worksheets+pdf PDF link annotation
    • https://cdn.sqhk.co/taxeseta/bwjfvef/helix_weed_games.pdfIn PDF document text
    • http://nemosixumeki.mypressonline.com/add_watermark_adobe_pro.pdfIn PDF document text
    • https://cdn.sqhk.co/xivovido/iihhjda/one_gun_stickman_unlimited_money.pdfIn PDF document text
    • https://vesanawe.weebly.com/uploads/1/3/4/6/134602832/tesitawof_nosilixupazo_jorolevejatizu_bomajakeni.pdfIn PDF document text
    • https://jibowosiz.weebly.com/uploads/1/3/4/6/134632869/4603150.pdfIn PDF document text
    • http://lebedugipul.mywebcommunity.org/ninamap.pdfIn PDF document text
    • http://pazujiz.mygamesonline.org/active_voice_and_passive_voice_exercises.pdfIn PDF document text
    • https://pusavipesuxa.weebly.com/uploads/1/3/1/4/131406286/purofev.pdfIn PDF document text
    • https://zumikifekov.weebly.com/uploads/1/3/0/8/130813997/wexos.pdfIn PDF document text
    • https://gisunada.weebly.com/uploads/1/3/1/4/131409009/jaxilegen.pdfIn PDF document text
    • https://xojurumute.weebly.com/uploads/1/3/5/3/135328527/6328961.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://6525eaf8-9a42-4119-9fb4-c3d475b3b78e.filesusr.com/ugd/80bfa9_f25c0392a5bb4554909b7632ca2fe08c.pdf?index=trueIn PDF document text
    • https://f6ea5e03-7e7c-4dce-82ee-fd5d223759ef.filesusr.com/ugd/d203ad_ebfd977420a44dbeab905f56a5d58380.pdf?index=trueIn PDF document text
    • http://pekowob.onlinewebshop.net/uses_of_acetic_acid.pdfIn PDF document text
    • http://jadigilotuziwir.rf.gd/alfabeto_portugus_completo.pdfIn PDF document text
    • http://tevefetilojas.atwebpages.com/the_pleiadian_tantric_workbook.pdfIn PDF document text
    • http://kijolitenelofon.epizy.com/77655194847.pdfIn PDF document text
    • https://87164119-88a6-4d6d-a72f-b109cf2d88b9.filesusr.com/ugd/bd0a66_6fbfde6cf87342b0a8ad6abade7ddcba.pdf?index=trueIn PDF document text
    • https://2ea3657d-1c4c-40dd-8491-58aeeb8dc933.filesusr.com/ugd/18a85a_bff1ed9db1924cff84233576ac1b2a96.pdf?index=trueIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ecfb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECFB 5544 bytes
SHA-256: c60d6dd3f81b014f9741ed95dff183f0356044a055e8396fe9917a3c7705fb7a
font_01_sfnt_off0000ffee.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFEE 11076 bytes
SHA-256: 24206b2731b79248f124cf4fdfd0c1005f78e943e221bfbf9eaa8d20f183559f