Malicious PDF — malware analysis report

Static analysis result for SHA-256 8fd405b9ae1364f8…

MALICIOUS

PDF

90.3 KB Created: 2021-04-04 07:07:06 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 4c86ebb05a28d642d6d05a0e846e0f72 SHA-1: 14caaa63cb0264f0eb892e4787e325f8c87835e3 SHA-256: 8fd405b9ae1364f8225ae4090a00b8a614314426331cfbf053a1227da13c0e07
226 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript T1203 Exploitation for Client Execution

The PDF contains a large number of external links, many hosted on disposable domains, suggesting a link farm or SEO poisoning attack. The document body, though heavily obfuscated, appears to be a lure related to search queries. The presence of PDF_SEO_LINK_FARM and SE_CLICKFIX heuristics indicates a social engineering attempt to redirect users to malicious sites. ClamAV detection and ML classification confirm its malicious nature, likely as a phishing or trojan delivery mechanism.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9961

Heuristics 7

  • 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.
  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • ClickFix social engineering attack high SE_CLICKFIX
    Document instructs the user to press Win+R or paste a command into a terminal — consistent with ClickFix attacks that bypass macro restrictions by tricking users into running malicious commands directly
  • 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://vilenefex.ru/strik?utm_term=how+many+carbs+in+a+dunkin+donuts+sesame+bagel
    • https://pevusipifo.weebly.com/uploads/1/3/4/8/134863194/1b7212b7fd33.pdf
    • https://dopakegufa.weebly.com/uploads/1/3/1/3/131384718/rijozezinavizukow.pdf
    • http://dipufuvolog.iblogger.org/53348119311.pdf
    • https://sebinegovana.weebly.com/uploads/1/3/4/0/134095930/8797026.pdf
    • https://lezevonunibo.weebly.com/uploads/1/3/4/5/134577944/ridulibilezumavef.pdf
    • https://mukeluxera.weebly.com/uploads/1/3/4/5/134528716/pikibibakejexiduva.pdf
    • https://fakebomazeb.weebly.com/uploads/1/3/1/4/131453402/tijelutov.pdf
    • http://tajavimisafom.22web.org/outlook_out_of_office_holiday_template.pdf
    • https://zokelafeg.weebly.com/uploads/1/3/4/8/134889419/6ee40617821fcd2.pdf
    • https://bijawodit.weebly.com/uploads/1/3/4/8/134883407/4d1c47e2b158.pdf
    • https://lepabamun.weebly.com/uploads/1/3/1/6/131636917/1ee4e8.pdf
    • https://repemokalit.weebly.com/uploads/1/3/1/8/131856723/4224951.pdf
    • https://pumelagu.weebly.com/uploads/1/3/2/8/132814433/resifajese_nanakage_logijemuwux_zuvivefitujope.pdf
    • https://muwirejevom.weebly.com/uploads/1/3/1/8/131857435/vukebavusi_lusosedenadid.pdf
    • https://susemozud.weebly.com/uploads/1/3/2/8/132814624/minajadu_kusefokopob_fubodivazis.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • http://furovival.rf.gd/jama_sepsis_2020_espaol.pdf
    • https://s3.amazonaws.com/bokexizometun/dns-320l_custom_firmware.pdf
    • https://uploads.strikinglycdn.com/files/3e64fca4-97a2-48e1-bd91-92c9b980d1ff/sijasexibuvuvoxolujoki.pdf
    • https://uploads.strikinglycdn.com/files/b9a2a908-cbbf-4ec3-b836-e1699af05dad/max_lucado_inspirational_study_bible_large_print.pdf
    • https://s3.amazonaws.com/zuvovoxigumuz/bolagomudub.pdf
    • https://uploads.strikinglycdn.com/files/51c80d29-2a28-4077-92b9-def932de8b2a/radionovela_chucho_el_roto_wikipedia.pdf
    • https://uploads.strikinglycdn.com/files/d150279e-891f-45e2-9a37-e43ff5e4dfa1/gozibubilewera.pdf
    • https://s3.amazonaws.com/bubisifapagefe/52137040293.pdf
    • http://xopidevuk.rf.gd/68857639350.pdf
    • https://uploads.strikinglycdn.com/files/549a2930-cb86-4f43-bdcd-9c3cfe9e25dc/66711185677.pdf
    • https://s3.amazonaws.com/kexamoxusinixu/mafafojenujuxuxijipur.pdf
    • http://demuremapinob.epizy.com/patalaworajibevuvobe.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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012112.bin
ad9a51e2ff4bf13a0e9c34dba83a9dacaa7fb94a34eafde2ac0f4b791d4a168a
pdf-font-stream PDF embedded font (sfnt) at offset 0x12112 5620 bytes
font_01_sfnt_off00013426.bin
5cd0446aaa7a58fc3c91c3b037fc4dbcdee9cf9a73ad2a699938243c2326efdc
pdf-font-stream PDF embedded font (sfnt) at offset 0x13426 11340 bytes